Bug 1454696 - Run eslint --fix for prefer-const;r=yulia

MozReview-Commit-ID: F6xUXCgdRE4

--HG--
extra : rebase_source : 65de1b0aba412d9044b5196115f74276caa058f2

devtools/client/aboutdebugging/components/Aboutdebugging.js

@@ -89,10 +89,10 @@ class AboutDebuggingApp extends Component {
   }
 
   render() {
-    let { client, connect } = this.props;
-    let { selectedPanelId } = this.state;
-    let selectPanel = this.selectPanel;
-    let selectedPanel = panels.find(p => p.id == selectedPanelId);
+    const { client, connect } = this.props;
+    const { selectedPanelId } = this.state;
+    const selectPanel = this.selectPanel;
+    const selectedPanel = panels.find(p => p.id == selectedPanelId);
     let panel;
 
     if (selectedPanel) {

devtools/client/aboutdebugging/components/PanelHeader.js

@@ -17,7 +17,7 @@ class PanelHeader extends Component {
   }
 
   render() {
-    let { name, id } = this.props;
+    const { name, id } = this.props;
 
     return dom.div({ className: "header" },
       dom.h1({ id, className: "header-name" }, name));

devtools/client/aboutdebugging/components/PanelMenu.js

@@ -24,9 +24,9 @@ class PanelMenu extends Component {
   }
 
   render() {
-    let { panels, selectedPanelId, selectPanel } = this.props;
-    let panelLinks = panels.map(({ id, name, icon }) => {
-      let selected = id == selectedPanelId;
+    const { panels, selectedPanelId, selectPanel } = this.props;
+    const panelLinks = panels.map(({ id, name, icon }) => {
+      const selected = id == selectedPanelId;
       return PanelMenuEntry({
         id,
         name,

devtools/client/aboutdebugging/components/PanelMenuEntry.js

@@ -29,11 +29,11 @@ class PanelMenuEntry extends Component {
   }
 
   render() {
-    let { id, name, icon, selected } = this.props;
+    const { id, name, icon, selected } = this.props;
 
     // Here .category, .category-icon, .category-name classnames are used to
     // apply common styles defined.
-    let className = "category" + (selected ? " selected" : "");
+    const className = "category" + (selected ? " selected" : "");
     return dom.button({
       "aria-selected": selected,
       "aria-controls": id + "-panel",

devtools/client/aboutdebugging/components/addons/Controls.js

@@ -44,14 +44,14 @@ class AddonsControls extends Component {
   }
 
   onEnableAddonDebuggingChange(event) {
-    let enabled = event.target.checked;
+    const enabled = event.target.checked;
     Services.prefs.setBoolPref("devtools.chrome.enabled", enabled);
     Services.prefs.setBoolPref("devtools.debugger.remote-enabled", enabled);
   }
 
   loadAddonFromFile() {
     this.setState({ installError: null });
-    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+    const fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
     fp.init(window,
       Strings.GetStringFromName("selectAddonFromFile2"),
       Ci.nsIFilePicker.modeOpen);
@@ -88,7 +88,7 @@ class AddonsControls extends Component {
   }
 
   render() {
-    let { debugDisabled } = this.props;
+    const { debugDisabled } = this.props;
 
     return dom.div({ className: "addons-top" },
       dom.div({ className: "addons-controls" },

devtools/client/aboutdebugging/components/addons/InstallError.js

@@ -26,7 +26,7 @@ class AddonsInstallError extends Component {
     if (!this.props.error) {
       return null;
     }
-    let text = Strings.formatStringFromName("addonInstallError", [this.props.error], 1);
+    const text = Strings.formatStringFromName("addonInstallError", [this.props.error], 1);
     return dom.div(
       { className: "addons-install-error" },
       dom.span(

devtools/client/aboutdebugging/components/addons/Panel.js

@@ -79,7 +79,7 @@ class AddonsPanel extends Component {
   }
 
   updateDebugStatus() {
-    let debugDisabled =
+    const debugDisabled =
       !Services.prefs.getBoolPref(CHROME_ENABLED_PREF) ||
       !Services.prefs.getBoolPref(REMOTE_ENABLED_PREF);
 
@@ -89,7 +89,7 @@ class AddonsPanel extends Component {
   updateAddonsList() {
     this.props.client.listAddons()
       .then(({addons}) => {
-        let extensions = addons.filter(addon => addon.debuggable).map(addon => {
+        const extensions = addons.filter(addon => addon.debuggable).map(addon => {
           return {
             addonActor: addon.actor,
             addonID: addon.id,
@@ -139,11 +139,11 @@ class AddonsPanel extends Component {
   }
 
   render() {
-    let { client, connect, id } = this.props;
-    let { debugDisabled, extensions: targets } = this.state;
-    let installedName = Strings.GetStringFromName("extensions");
-    let temporaryName = Strings.GetStringFromName("temporaryExtensions");
-    let targetClass = AddonTarget;
+    const { client, connect, id } = this.props;
+    const { debugDisabled, extensions: targets } = this.state;
+    const installedName = Strings.GetStringFromName("extensions");
+    const temporaryName = Strings.GetStringFromName("temporaryExtensions");
+    const targetClass = AddonTarget;
 
     const installedTargets = targets.filter((target) => !target.temporarilyInstalled);
     const temporaryTargets = targets.filter((target) => target.temporarilyInstalled);

devtools/client/aboutdebugging/components/addons/Target.js

@@ -34,7 +34,7 @@ function filePathForTarget(target) {
   if (!target.temporarilyInstalled || !target.url || !target.url.startsWith("file://")) {
     return [];
   }
-  let path = parseFileUri(target.url);
+  const path = parseFileUri(target.url);
   return [
     dom.dt(
       { className: "addon-target-info-label" },
@@ -69,7 +69,7 @@ function internalIDForTarget(target) {
     return [];
   }
   // Strip off the protocol and rest, leaving us with just the UUID.
-  let uuid = /moz-extension:\/\/([^/]*)/.exec(target.manifestURL)[1];
+  const uuid = /moz-extension:\/\/([^/]*)/.exec(target.manifestURL)[1];
   return [
     dom.dt(
       { className: "addon-target-info-label" },
@@ -139,7 +139,7 @@ function warningMessages(target) {
     ));
   }
 
-  let warnings = target.warnings || [];
+  const warnings = target.warnings || [];
   messages = messages.concat(warnings.map((warning) => {
     return dom.li(
       { className: "addon-target-warning-message addon-target-message" },
@@ -176,7 +176,7 @@ class AddonTarget extends Component {
   }
 
   debug() {
-    let { client, connect, target } = this.props;
+    const { client, connect, target } = this.props;
 
     if (connect.type === "REMOTE") {
       debugRemoteAddon(target.form, client);
@@ -186,13 +186,13 @@ class AddonTarget extends Component {
   }
 
   uninstall() {
-    let { target } = this.props;
+    const { target } = this.props;
     uninstallAddon(target.addonID);
   }
 
   async reload() {
-    let { client, target } = this.props;
-    let { AboutDebugging } = window;
+    const { client, target } = this.props;
+    const { AboutDebugging } = window;
     try {
       await client.request({
         to: target.addonActor,
@@ -205,7 +205,7 @@ class AddonTarget extends Component {
   }
 
   render() {
-    let { target, debugDisabled } = this.props;
+    const { target, debugDisabled } = this.props;
 
     return dom.li(
       { className: "addon-target-container", "data-addon-id": target.addonID },

devtools/client/aboutdebugging/components/tabs/Panel.js

@@ -41,13 +41,13 @@ class TabsPanel extends Component {
   }
 
   componentDidMount() {
-    let { client } = this.props;
+    const { client } = this.props;
     client.addListener("tabListChanged", this.update);
     this.update();
   }
 
   componentWillUnmount() {
-    let { client } = this.props;
+    const { client } = this.props;
     client.removeListener("tabListChanged", this.update);
   }
 
@@ -57,9 +57,9 @@ class TabsPanel extends Component {
     // Filter out closed tabs (represented as `null`).
     tabs = tabs.filter(tab => !!tab);
 
-    for (let tab of tabs) {
+    for (const tab of tabs) {
       if (tab.favicon) {
-        let base64Favicon = btoa(String.fromCharCode.apply(String, tab.favicon));
+        const base64Favicon = btoa(String.fromCharCode.apply(String, tab.favicon));
         tab.icon = "data:image/png;base64," + base64Favicon;
       } else {
         tab.icon = "chrome://devtools/skin/images/globe.svg";
@@ -70,8 +70,8 @@ class TabsPanel extends Component {
   }
 
   render() {
-    let { client, connect, id } = this.props;
-    let { tabs } = this.state;
+    const { client, connect, id } = this.props;
+    const { tabs } = this.state;
 
     return dom.div({
       id: id + "-panel",

devtools/client/aboutdebugging/components/tabs/Target.js

@@ -34,17 +34,17 @@ class TabTarget extends Component {
   }
 
   debug() {
-    let { target, connect } = this.props;
+    const { target, connect } = this.props;
     let url = "about:devtools-toolbox?type=tab&id=" + target.outerWindowID;
     if (connect.type == "REMOTE") {
-      let {host, port} = connect.params;
+      const {host, port} = connect.params;
       url += `&host=${encodeURIComponent(host)}&port=${encodeURIComponent(port)}`;
     }
     window.open(url);
   }
 
   render() {
-    let { target } = this.props;
+    const { target } = this.props;
 
     return dom.div({ className: "target-container" },
       dom.img({

devtools/client/aboutdebugging/components/workers/MultiE10sWarning.js

@@ -21,7 +21,7 @@ class multiE10SWarning extends Component {
   }
 
   onUpdatePreferenceClick() {
-    let message = Strings.GetStringFromName("multiProcessWarningConfirmUpdate2");
+    const message = Strings.GetStringFromName("multiProcessWarningConfirmUpdate2");
     if (window.confirm(message)) {
       // Disable multi until at least the next experiment.
       Services.prefs.setIntPref(MULTI_OPT_OUT_PREF,

devtools/client/aboutdebugging/components/workers/Panel.js

@@ -53,7 +53,7 @@ class WorkersPanel extends Component {
   }
 
   componentDidMount() {
-    let client = this.props.client;
+    const client = this.props.client;
     client.addListener("workerListChanged", this.updateWorkers);
     client.addListener("serviceWorkerRegistrationListChanged", this.updateWorkers);
     client.addListener("processListChanged", this.updateWorkers);
@@ -79,7 +79,7 @@ class WorkersPanel extends Component {
   }
 
   componentWillUnmount() {
-    let client = this.props.client;
+    const client = this.props.client;
     client.removeListener("processListChanged", this.updateWorkers);
     client.removeListener("serviceWorkerRegistrationListChanged", this.updateWorkers);
     client.removeListener("workerListChanged", this.updateWorkers);
@@ -103,12 +103,12 @@ class WorkersPanel extends Component {
   updateMultiE10S() {
     // We watch the pref but set the state based on
     // nsIXULRuntime.maxWebProcessCount.
-    let processCount = Services.appinfo.maxWebProcessCount;
+    const processCount = Services.appinfo.maxWebProcessCount;
     this.setState({ processCount });
   }
 
   updateWorkers() {
-    let workers = this.initialState.workers;
+    const workers = this.initialState.workers;
 
     this.props.client.mainRoot.listAllWorkers().then(({service, other, shared}) => {
       workers.service = service.map(f => Object.assign({ icon: WorkerIcon }, f));
@@ -128,12 +128,12 @@ class WorkersPanel extends Component {
   }
 
   renderServiceWorkersError() {
-    let isWindowPrivate = PrivateBrowsingUtils.isContentWindowPrivate(window);
-    let isPrivateBrowsingMode = PrivateBrowsingUtils.permanentPrivateBrowsing;
-    let isServiceWorkerDisabled = !Services.prefs
+    const isWindowPrivate = PrivateBrowsingUtils.isContentWindowPrivate(window);
+    const isPrivateBrowsingMode = PrivateBrowsingUtils.permanentPrivateBrowsing;
+    const isServiceWorkerDisabled = !Services.prefs
                                     .getBoolPref("dom.serviceWorkers.enabled");
 
-    let isDisabled = isWindowPrivate || isPrivateBrowsingMode || isServiceWorkerDisabled;
+    const isDisabled = isWindowPrivate || isPrivateBrowsingMode || isServiceWorkerDisabled;
     if (!isDisabled) {
       return "";
     }
@@ -159,11 +159,11 @@ class WorkersPanel extends Component {
   }
 
   render() {
-    let { client, id } = this.props;
-    let { workers, processCount } = this.state;
+    const { client, id } = this.props;
+    const { workers, processCount } = this.state;
 
-    let isE10S = Services.appinfo.browserTabsRemoteAutostart;
-    let isMultiE10S = isE10S && processCount > 1;
+    const isE10S = Services.appinfo.browserTabsRemoteAutostart;
+    const isMultiE10S = isE10S && processCount > 1;
 
     return dom.div(
       {

devtools/client/aboutdebugging/components/workers/ServiceWorkerTarget.js

@@ -59,13 +59,13 @@ class ServiceWorkerTarget extends Component {
   }
 
   componentDidMount() {
-    let { client } = this.props;
+    const { client } = this.props;
     client.addListener("push-subscription-modified", this.onPushSubscriptionModified);
     this.updatePushSubscription();
   }
 
   componentDidUpdate(oldProps, oldState) {
-    let wasActive = oldProps.target.active;
+    const wasActive = oldProps.target.active;
     if (!wasActive && this.isActive()) {
       // While the service worker isn't active, any calls to `updatePushSubscription`
       // won't succeed. If we just became active, make sure we didn't miss a push
@@ -75,7 +75,7 @@ class ServiceWorkerTarget extends Component {
   }
 
   componentWillUnmount() {
-    let { client } = this.props;
+    const { client } = this.props;
     client.removeListener("push-subscription-modified", this.onPushSubscriptionModified);
   }
 
@@ -85,7 +85,7 @@ class ServiceWorkerTarget extends Component {
       return;
     }
 
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     gDevToolsBrowser.openWorkerToolbox(client, target.workerActor);
   }
 
@@ -97,7 +97,7 @@ class ServiceWorkerTarget extends Component {
       return;
     }
 
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     client.request({
       to: target.workerActor,
       type: "push"
@@ -110,7 +110,7 @@ class ServiceWorkerTarget extends Component {
       return;
     }
 
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     client.request({
       to: target.registrationActor,
       type: "start"
@@ -118,7 +118,7 @@ class ServiceWorkerTarget extends Component {
   }
 
   unregister() {
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     client.request({
       to: target.registrationActor,
       type: "unregister"
@@ -126,7 +126,7 @@ class ServiceWorkerTarget extends Component {
   }
 
   onPushSubscriptionModified(type, data) {
-    let { target } = this.props;
+    const { target } = this.props;
     if (data.from === target.registrationActor) {
       this.updatePushSubscription();
     }
@@ -138,7 +138,7 @@ class ServiceWorkerTarget extends Component {
       return;
     }
 
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     client.request({
       to: target.registrationActor,
       type: "getPushSubscription"
@@ -169,19 +169,19 @@ class ServiceWorkerTarget extends Component {
   }
 
   renderButtons() {
-    let pushButton = dom.button({
+    const pushButton = dom.button({
       className: "push-button",
       onClick: this.push,
       disabled: this.props.debugDisabled
     }, Strings.GetStringFromName("push"));
 
-    let debugButton = dom.button({
+    const debugButton = dom.button({
       className: "debug-button",
       onClick: this.debug,
       disabled: this.props.debugDisabled
     }, Strings.GetStringFromName("debug"));
 
-    let startButton = dom.button({
+    const startButton = dom.button({
       className: "start-button",
       onClick: this.start,
       disabled: this.props.debugDisabled
@@ -210,11 +210,11 @@ class ServiceWorkerTarget extends Component {
   }
 
   render() {
-    let { target } = this.props;
-    let { pushSubscription } = this.state;
-    let status = this.getServiceWorkerStatus();
+    const { target } = this.props;
+    const { pushSubscription } = this.state;
+    const status = this.getServiceWorkerStatus();
 
-    let fetch = target.fetch ? Strings.GetStringFromName("listeningForFetchEvents") :
+    const fetch = target.fetch ? Strings.GetStringFromName("listeningForFetchEvents") :
       Strings.GetStringFromName("notListeningForFetchEvents");
 
     return dom.div({ className: "target-container" },

devtools/client/aboutdebugging/components/workers/Target.js

@@ -38,12 +38,12 @@ class WorkerTarget extends Component {
   }
 
   debug() {
-    let { client, target } = this.props;
+    const { client, target } = this.props;
     gDevToolsBrowser.openWorkerToolbox(client, target.workerActor);
   }
 
   render() {
-    let { target, debugDisabled } = this.props;
+    const { target, debugDisabled } = this.props;
 
     return dom.li({ className: "target-container" },
       dom.img({

devtools/client/aboutdebugging/initializer.js

@@ -37,12 +37,12 @@ var AboutDebugging = {
       return;
     }
 
-    let {connect, client} = await createClient();
+    const {connect, client} = await createClient();
 
     this.client = client;
     await this.client.connect();
 
-    let telemetry = new Telemetry();
+    const telemetry = new Telemetry();
 
     render(AboutDebuggingApp({ client, connect, telemetry }),
       document.querySelector("#body"));

devtools/client/aboutdebugging/modules/addon.js

@@ -56,16 +56,16 @@ exports.debugRemoteAddon = async function(addonForm, client) {
   // Close previous addon debugging toolbox.
   closeToolbox();
 
-  let options = {
+  const options = {
     form: addonForm,
     chrome: true,
     client,
     isTabActor: addonForm.isWebExtension
   };
 
-  let target = await TargetFactory.forRemoteTab(options);
+  const target = await TargetFactory.forRemoteTab(options);
 
-  let hostType = Toolbox.HostType.WINDOW;
+  const hostType = Toolbox.HostType.WINDOW;
   remoteAddonToolbox = await gDevTools.showToolbox(target, null, hostType);
   remoteAddonToolbox.once("destroy", () => {
     remoteAddonToolbox = null;
@@ -73,7 +73,7 @@ exports.debugRemoteAddon = async function(addonForm, client) {
 };
 
 exports.uninstallAddon = async function(addonID) {
-  let addon = await AddonManager.getAddonByID(addonID);
+  const addon = await AddonManager.getAddonByID(addonID);
   return addon && addon.uninstall();
 };
 

devtools/client/aboutdebugging/modules/connect.js

@@ -33,10 +33,10 @@ const TYPE = {
  *            - if type === "REMOTE", {host: {String}, port: {String}}
  */
 function createDescriptorFromURL(url) {
-  let params = url.searchParams;
+  const params = url.searchParams;
 
-  let host = params.get("host");
-  let port = params.get("port");
+  const host = params.get("host");
+  const port = params.get("port");
 
   let descriptor;
   if (host && port) {
@@ -63,11 +63,11 @@ function createDescriptorFromURL(url) {
  *          - connect: a connection descriptor, see doc for createDescriptorFromURL(url).
  */
 exports.createClient = async function() {
-  let href = window.location.href;
-  let url = new window.URL(href.replace("about:", "http://"));
+  const href = window.location.href;
+  const url = new window.URL(href.replace("about:", "http://"));
 
-  let connect = createDescriptorFromURL(url);
-  let client = await clientFromURL(url);
+  const connect = createDescriptorFromURL(url);
+  const client = await clientFromURL(url);
 
   DebuggerServer.allowChromeProcess = true;
 

devtools/client/aboutdebugging/test/browser_addons_debug_bootstrapped.js

@@ -17,7 +17,7 @@ const { BrowserToolboxProcess } = ChromeUtils.import("resource://devtools/client
 
 add_task(async function() {
   await new Promise(resolve => {
-    let options = {"set": [
+    const options = {"set": [
       // Force enabling of addons debugging
       ["devtools.chrome.enabled", true],
       ["devtools.debugger.remote-enabled", true],
@@ -29,7 +29,7 @@ add_task(async function() {
     SpecialPowers.pushPrefEnv(options, resolve);
   });
 
-  let { tab, document } = await openAboutDebugging("addons");
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
   await installAddon({
     document,
@@ -38,16 +38,16 @@ add_task(async function() {
   });
 
   // Retrieve the DEBUG button for the addon
-  let names = getInstalledAddonNames(document);
-  let name = names.filter(element => element.textContent === ADDON_NAME)[0];
+  const names = getInstalledAddonNames(document);
+  const name = names.filter(element => element.textContent === ADDON_NAME)[0];
   ok(name, "Found the addon in the list");
-  let targetElement = name.parentNode.parentNode;
-  let debugBtn = targetElement.querySelector(".debug-button");
+  const targetElement = name.parentNode.parentNode;
+  const debugBtn = targetElement.querySelector(".debug-button");
   ok(debugBtn, "Found its debug button");
 
   // Wait for a notification sent by a script evaluated the test addon via
   // the web console.
-  let onCustomMessage = new Promise(done => {
+  const onCustomMessage = new Promise(done => {
     Services.obs.addObserver(function listener() {
       Services.obs.removeObserver(listener, "addon-console-works");
       done();
@@ -56,13 +56,13 @@ add_task(async function() {
 
   // Be careful, this JS function is going to be executed in the addon toolbox,
   // which lives in another process. So do not try to use any scope variable!
-  let env = Cc["@mozilla.org/process/environment;1"]
+  const env = Cc["@mozilla.org/process/environment;1"]
               .getService(Ci.nsIEnvironment);
-  let testScript = function() {
+  const testScript = function() {
     /* eslint-disable no-undef */
     toolbox.selectTool("webconsole")
       .then(console => {
-        let { jsterm } = console.hud;
+        const { jsterm } = console.hud;
         return jsterm.execute("myBootstrapAddonFunction()");
       })
       .then(() => toolbox.destroy());
@@ -73,7 +73,7 @@ add_task(async function() {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let onToolboxClose = BrowserToolboxProcess.once("close");
+  const onToolboxClose = BrowserToolboxProcess.once("close");
 
   debugBtn.click();
 

devtools/client/aboutdebugging/test/browser_addons_debug_info.js

@@ -4,16 +4,16 @@ const UUID_REGEX = /^([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{1
 
 function testFilePath(container, expectedFilePath) {
   // Verify that the path to the install location is shown next to its label.
-  let filePath = container.querySelector(".file-path");
+  const filePath = container.querySelector(".file-path");
   ok(filePath, "file path is in DOM");
   ok(filePath.textContent.endsWith(expectedFilePath), "file path is set correctly");
   is(filePath.previousElementSibling.textContent, "Location", "file path has label");
 }
 
 add_task(async function testLegacyAddon() {
-  let addonId = "test-devtools@mozilla.org";
-  let addonName = "test-devtools";
-  let { tab, document } = await openAboutDebugging("addons");
+  const addonId = "test-devtools@mozilla.org";
+  const addonName = "test-devtools";
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   await installAddon({
@@ -22,7 +22,7 @@ add_task(async function testLegacyAddon() {
     name: addonName,
   });
 
-  let container = document.querySelector(`[data-addon-id="${addonId}"]`);
+  const container = document.querySelector(`[data-addon-id="${addonId}"]`);
   testFilePath(container, "browser/devtools/client/aboutdebugging/test/addons/unpacked/");
 
   await uninstallAddon({document, id: addonId, name: addonName});
@@ -31,9 +31,9 @@ add_task(async function testLegacyAddon() {
 });
 
 add_task(async function testWebExtension() {
-  let addonId = "test-devtools-webextension-nobg@mozilla.org";
-  let addonName = "test-devtools-webextension-nobg";
-  let { tab, document } = await openAboutDebugging("addons");
+  const addonId = "test-devtools-webextension-nobg@mozilla.org";
+  const addonName = "test-devtools-webextension-nobg";
+  const { tab, document } = await openAboutDebugging("addons");
 
   await waitForInitialAddonList(document);
   await installAddon({
@@ -43,16 +43,16 @@ add_task(async function testWebExtension() {
     isWebExtension: true
   });
 
-  let container = document.querySelector(`[data-addon-id="${addonId}"]`);
+  const container = document.querySelector(`[data-addon-id="${addonId}"]`);
   testFilePath(container, "/test/addons/test-devtools-webextension-nobg/");
 
-  let extensionID = container.querySelector(".extension-id span");
+  const extensionID = container.querySelector(".extension-id span");
   ok(extensionID.textContent === "test-devtools-webextension-nobg@mozilla.org");
 
-  let internalUUID = container.querySelector(".internal-uuid span");
+  const internalUUID = container.querySelector(".internal-uuid span");
   ok(internalUUID.textContent.match(UUID_REGEX), "internalUUID is correct");
 
-  let manifestURL = container.querySelector(".manifest-url");
+  const manifestURL = container.querySelector(".manifest-url");
   ok(manifestURL.href.startsWith("moz-extension://"), "href for manifestURL exists");
 
   await uninstallAddon({document, id: addonId, name: addonName});
@@ -61,8 +61,8 @@ add_task(async function testWebExtension() {
 });
 
 add_task(async function testTemporaryWebExtension() {
-  let addonName = "test-devtools-webextension-noid";
-  let { tab, document } = await openAboutDebugging("addons");
+  const addonName = "test-devtools-webextension-noid";
+  const { tab, document } = await openAboutDebugging("addons");
 
   await waitForInitialAddonList(document);
   await installAddon({
@@ -72,15 +72,15 @@ add_task(async function testTemporaryWebExtension() {
     isWebExtension: true
   });
 
-  let addons = document.querySelectorAll("#temporary-extensions .addon-target-container");
+  const addons = document.querySelectorAll("#temporary-extensions .addon-target-container");
   // Assuming that our temporary add-on is now at the top.
-  let container = addons[addons.length - 1];
-  let addonId = container.dataset.addonId;
+  const container = addons[addons.length - 1];
+  const addonId = container.dataset.addonId;
 
-  let extensionID = container.querySelector(".extension-id span");
+  const extensionID = container.querySelector(".extension-id span");
   ok(extensionID.textContent.endsWith("@temporary-addon"));
 
-  let temporaryID = container.querySelector(".temporary-id-url");
+  const temporaryID = container.querySelector(".temporary-id-url");
   ok(temporaryID, "Temporary ID message does appear");
 
   await uninstallAddon({document, id: addonId, name: addonName});
@@ -89,9 +89,9 @@ add_task(async function testTemporaryWebExtension() {
 });
 
 add_task(async function testUnknownManifestProperty() {
-  let addonId = "test-devtools-webextension-unknown-prop@mozilla.org";
-  let addonName = "test-devtools-webextension-unknown-prop";
-  let { tab, document } = await openAboutDebugging("addons");
+  const addonId = "test-devtools-webextension-unknown-prop@mozilla.org";
+  const addonName = "test-devtools-webextension-unknown-prop";
+  const { tab, document } = await openAboutDebugging("addons");
 
   await waitForInitialAddonList(document);
   await installAddon({
@@ -102,12 +102,12 @@ add_task(async function testUnknownManifestProperty() {
   });
 
   info("Wait until the addon appears in about:debugging");
-  let container = await waitUntilAddonContainer(addonName, document);
+  const container = await waitUntilAddonContainer(addonName, document);
 
   info("Wait until the installation message appears for the new addon");
   await waitUntilElement(".addon-target-messages", container);
 
-  let messages = container.querySelectorAll(".addon-target-message");
+  const messages = container.querySelectorAll(".addon-target-message");
   ok(messages.length === 1, "there is one message");
   ok(messages[0].textContent.match(/Error processing browser_actions/),
      "the message is helpful");

devtools/client/aboutdebugging/test/browser_addons_debug_webextension.js

@@ -25,15 +25,15 @@ const {
  *   has a working webconsole with the background page as default target;
  */
 add_task(async function testWebExtensionsToolboxWebConsole() {
-  let {
+  const {
     tab, document, debugBtn,
   } = await setupTestAboutDebuggingWebExtension(ADDON_NAME, ADDON_MANIFEST_PATH);
 
   // Be careful, this JS function is going to be executed in the addon toolbox,
   // which lives in another process. So do not try to use any scope variable!
-  let env = Cc["@mozilla.org/process/environment;1"]
+  const env = Cc["@mozilla.org/process/environment;1"]
               .getService(Ci.nsIEnvironment);
-  let testScript = function() {
+  const testScript = function() {
     /* eslint-disable no-undef */
     function findMessages(hud, text, selector = ".message") {
       const messages = hud.ui.outputNode.querySelectorAll(selector);
@@ -52,9 +52,9 @@ add_task(async function testWebExtensionsToolboxWebConsole() {
 
     toolbox.selectTool("webconsole")
       .then(async console => {
-        let { hud } = console;
-        let { jsterm } = hud;
-        let onMessage = waitFor(() => {
+        const { hud } = console;
+        const { jsterm } = hud;
+        const onMessage = waitFor(() => {
           return findMessages(hud, "Background page function called").length > 0;
         });
         await jsterm.execute("myWebExtensionAddonFunction()");
@@ -69,7 +69,7 @@ add_task(async function testWebExtensionsToolboxWebConsole() {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let onToolboxClose = BrowserToolboxProcess.once("close");
+  const onToolboxClose = BrowserToolboxProcess.once("close");
 
   debugBtn.click();
 

devtools/client/aboutdebugging/test/browser_addons_debug_webextension_inspector.js

@@ -24,15 +24,15 @@ const {
  *   background page as default target;
  */
 add_task(async function testWebExtensionsToolboxInspector() {
-  let {
+  const {
     tab, document, debugBtn,
   } = await setupTestAboutDebuggingWebExtension(ADDON_NAME, ADDON_PATH);
 
   // Be careful, this JS function is going to be executed in the addon toolbox,
   // which lives in another process. So do not try to use any scope variable!
-  let env = Cc["@mozilla.org/process/environment;1"]
+  const env = Cc["@mozilla.org/process/environment;1"]
         .getService(Ci.nsIEnvironment);
-  let testScript = function() {
+  const testScript = function() {
     /* eslint-disable no-undef */
     toolbox.selectTool("inspector")
       .then(inspector => {
@@ -51,8 +51,8 @@ add_task(async function testWebExtensionsToolboxInspector() {
 
         dump("Got a nodeActor with an inline text child\n");
 
-        let expectedValue = "Background Page Body Test Content";
-        let actualValue = nodeActor.inlineTextChild._form.nodeValue;
+        const expectedValue = "Background Page Body Test Content";
+        const actualValue = nodeActor.inlineTextChild._form.nodeValue;
 
         if (String(actualValue).trim() !== String(expectedValue).trim()) {
           throw new Error(
@@ -76,7 +76,7 @@ add_task(async function testWebExtensionsToolboxInspector() {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let onToolboxClose = BrowserToolboxProcess.once("close");
+  const onToolboxClose = BrowserToolboxProcess.once("close");
   debugBtn.click();
   await onToolboxClose;
 

devtools/client/aboutdebugging/test/browser_addons_debug_webextension_nobg.js

@@ -26,15 +26,15 @@ const {
  *   webextension context);
  */
 add_task(async function testWebExtensionsToolboxNoBackgroundPage() {
-  let {
+  const {
     tab, document, debugBtn,
   } = await setupTestAboutDebuggingWebExtension(ADDON_NOBG_NAME, ADDON_NOBG_PATH);
 
   // Be careful, this JS function is going to be executed in the addon toolbox,
   // which lives in another process. So do not try to use any scope variable!
-  let env = Cc["@mozilla.org/process/environment;1"]
+  const env = Cc["@mozilla.org/process/environment;1"]
         .getService(Ci.nsIEnvironment);
-  let testScript = function() {
+  const testScript = function() {
     /* eslint-disable no-undef */
     toolbox.selectTool("inspector")
       .then(inspector => {
@@ -53,8 +53,8 @@ add_task(async function testWebExtensionsToolboxNoBackgroundPage() {
 
         dump("Got a nodeActor with an inline text child\n");
 
-        let expectedValue = "Your addon does not have any document opened yet.";
-        let actualValue = nodeActor.inlineTextChild._form.nodeValue;
+        const expectedValue = "Your addon does not have any document opened yet.";
+        const actualValue = nodeActor.inlineTextChild._form.nodeValue;
 
         if (actualValue !== expectedValue) {
           throw new Error(
@@ -78,7 +78,7 @@ add_task(async function testWebExtensionsToolboxNoBackgroundPage() {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let onToolboxClose = BrowserToolboxProcess.once("close");
+  const onToolboxClose = BrowserToolboxProcess.once("close");
   debugBtn.click();
   await onToolboxClose;
 

devtools/client/aboutdebugging/test/browser_addons_debug_webextension_popup.js

@@ -76,15 +76,15 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
     onPopupCustomMessage = waitForExtensionTestMessage("popupPageFunctionCalled");
   });
 
-  let {
+  const {
     tab, document, debugBtn,
   } = await setupTestAboutDebuggingWebExtension(ADDON_NAME, ADDON_MANIFEST_PATH);
 
   // Be careful, this JS function is going to be executed in the addon toolbox,
   // which lives in another process. So do not try to use any scope variable!
-  let env = Cc["@mozilla.org/process/environment;1"].getService(Ci.nsIEnvironment);
+  const env = Cc["@mozilla.org/process/environment;1"].getService(Ci.nsIEnvironment);
 
-  let testScript = function() {
+  const testScript = function() {
     /* eslint-disable no-undef */
 
     let jsterm;
@@ -109,7 +109,7 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
         dump(`Clicked the menu button\n`);
 
         popupFramePromise = new Promise(resolve => {
-          let listener = data => {
+          const listener = data => {
             if (data.frames.some(({url}) => url && url.endsWith("popup.html"))) {
               toolbox.target.off("frame-update", listener);
               resolve();
@@ -118,7 +118,7 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
           toolbox.target.on("frame-update", listener);
         });
 
-        let waitForFrameListUpdate = toolbox.target.once("frame-update");
+        const waitForFrameListUpdate = toolbox.target.once("frame-update");
 
         jsterm = console.hud.jsterm;
         jsterm.execute("myWebExtensionShowPopup()");
@@ -131,19 +131,19 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
         ]);
 
         dump(`Clicking the frame list button\n`);
-        let btn = toolbox.doc.getElementById("command-button-frames");
-        let frameMenu = await toolbox.showFramesMenu({target: btn});
+        const btn = toolbox.doc.getElementById("command-button-frames");
+        const frameMenu = await toolbox.showFramesMenu({target: btn});
         dump(`Clicked the frame list button\n`);
 
         await frameMenu.once("open");
 
-        let frames = frameMenu.items;
+        const frames = frameMenu.items;
 
         if (frames.length != 2) {
           throw Error(`Number of frames found is wrong: ${frames.length} != 2`);
         }
 
-        let popupFrameBtn = frames.filter((frame) => {
+        const popupFrameBtn = frames.filter((frame) => {
           return frame.label.endsWith("popup.html");
         }).pop();
 
@@ -151,7 +151,7 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
           throw Error("Extension Popup frame not found in the listed frames");
         }
 
-        let waitForNavigated = toolbox.target.once("navigate");
+        const waitForNavigated = toolbox.target.once("navigate");
 
         popupFrameBtn.click();
 
@@ -173,20 +173,20 @@ add_task(async function testWebExtensionsToolboxSwitchToPopup() {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let onToolboxClose = BrowserToolboxProcess.once("close");
+  const onToolboxClose = BrowserToolboxProcess.once("close");
 
   debugBtn.click();
 
   await onReadyForOpenPopup;
 
-  let browserActionId = makeWidgetId(ADDON_ID) + "-browser-action";
-  let browserActionEl = window.document.getElementById(browserActionId);
+  const browserActionId = makeWidgetId(ADDON_ID) + "-browser-action";
+  const browserActionEl = window.document.getElementById(browserActionId);
 
   ok(browserActionEl, "Got the browserAction button from the browser UI");
   browserActionEl.click();
   info("Clicked on the browserAction button");
 
-  let args = await onPopupCustomMessage;
+  const args = await onPopupCustomMessage;
   ok(true, "Received console message from the popup page function as expected");
   is(args[0], "popupPageFunctionCalled", "Got the expected console message");
   is(args[1] && args[1].name, ADDON_NAME,

devtools/client/aboutdebugging/test/browser_addons_debugging_initial_state.js

@@ -31,7 +31,7 @@ const TEST_DATA = [
 ];
 
 add_task(async function() {
-  for (let testData of TEST_DATA) {
+  for (const testData of TEST_DATA) {
     await testCheckboxState(testData);
   }
 });
@@ -39,14 +39,14 @@ add_task(async function() {
 async function testCheckboxState(testData) {
   info("Set preferences as defined by the current test data.");
   await new Promise(resolve => {
-    let options = {"set": [
+    const options = {"set": [
       ["devtools.chrome.enabled", testData.chromeEnabled],
       ["devtools.debugger.remote-enabled", testData.debuggerRemoteEnable],
     ]};
     SpecialPowers.pushPrefEnv(options, resolve);
   });
 
-  let { tab, document } = await openAboutDebugging("addons");
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   info("Install a test addon.");
@@ -57,12 +57,12 @@ async function testCheckboxState(testData) {
   });
 
   info("Test checkbox checked state.");
-  let addonDebugCheckbox = document.querySelector("#enable-addon-debugging");
+  const addonDebugCheckbox = document.querySelector("#enable-addon-debugging");
   is(addonDebugCheckbox.checked, testData.expected,
     "Addons debugging checkbox should be in expected state.");
 
   info("Test debug buttons disabled state.");
-  let debugButtons = [...document.querySelectorAll("#addons .debug-button")];
+  const debugButtons = [...document.querySelectorAll("#addons .debug-button")];
   ok(debugButtons.every(b => b.disabled != testData.expected),
     "Debug buttons should be in the expected state");
 

devtools/client/aboutdebugging/test/browser_addons_install.js

@@ -12,7 +12,7 @@ const ADDON_NAME = "test-devtools";
 
 function mockFilePicker(window, file) {
   // Mock the file picker to select a test addon
-  let MockFilePicker = SpecialPowers.MockFilePicker;
+  const MockFilePicker = SpecialPowers.MockFilePicker;
   MockFilePicker.init(window);
   MockFilePicker.setFiles([file]);
 }
@@ -27,7 +27,7 @@ function mockFilePicker(window, file) {
  * @return {Promise} Promise that resolves to the output folder when done.
  */
 function promiseWriteWebManifestForExtension(manifest, dir) {
-  let files = {
+  const files = {
     "manifest.json": JSON.stringify(manifest),
   };
   return AddonTestUtils.promiseWriteFilesToExtension(
@@ -35,7 +35,7 @@ function promiseWriteWebManifestForExtension(manifest, dir) {
 }
 
 add_task(async function testLegacyInstallSuccess() {
-  let { tab, document } = await openAboutDebugging("addons");
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   // Install this add-on, and verify that it appears in the about:debugging UI
@@ -52,7 +52,7 @@ add_task(async function testLegacyInstallSuccess() {
 });
 
 add_task(async function testWebextensionInstallError() {
-  let { tab, document, window } = await openAboutDebugging("addons");
+  const { tab, document, window } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   // Trigger the file picker by clicking on the button
@@ -60,20 +60,20 @@ add_task(async function testWebextensionInstallError() {
   document.getElementById("load-addon-from-file").click();
 
   info("wait for the install error to appear");
-  let top = document.querySelector(".addons-top");
+  const top = document.querySelector(".addons-top");
   await waitUntilElement(".addons-install-error", top);
 
   await closeAboutDebugging(tab);
 });
 
 add_task(async function testWebextensionInstallErrorRetry() {
-  let { tab, document, window } = await openAboutDebugging("addons");
+  const { tab, document, window } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
-  let tempdir = AddonTestUtils.tempDir.clone();
-  let addonId = "invalid-addon-install-retry@mozilla.org";
-  let addonName = "invalid-addon-install-retry";
-  let manifest = {
+  const tempdir = AddonTestUtils.tempDir.clone();
+  const addonId = "invalid-addon-install-retry@mozilla.org";
+  const addonName = "invalid-addon-install-retry";
+  const manifest = {
     name: addonName,
     description: "test invalid-addon-install-retry",
     // eslint-disable-next-line camelcase
@@ -88,7 +88,7 @@ add_task(async function testWebextensionInstallErrorRetry() {
   await promiseWriteWebManifestForExtension(manifest, tempdir);
 
   // Mock the file picker to select a test addon.
-  let manifestFile = tempdir.clone();
+  const manifestFile = tempdir.clone();
   manifestFile.append(addonId, "manifest.json");
   mockFilePicker(window, manifestFile);
 
@@ -96,10 +96,10 @@ add_task(async function testWebextensionInstallErrorRetry() {
   document.getElementById("load-addon-from-file").click();
 
   info("wait for the install error to appear");
-  let top = document.querySelector(".addons-top");
+  const top = document.querySelector(".addons-top");
   await waitUntilElement(".addons-install-error", top);
 
-  let retryButton = document.querySelector("button.addons-install-retry");
+  const retryButton = document.querySelector("button.addons-install-retry");
   is(retryButton.textContent, "Retry", "Retry button has a good label");
 
   // Fix the manifest so the add-on will install.
@@ -110,7 +110,7 @@ add_task(async function testWebextensionInstallErrorRetry() {
   }];
   await promiseWriteWebManifestForExtension(manifest, tempdir);
 
-  let addonEl = document.querySelector(`[data-addon-id="${addonId}"]`);
+  const addonEl = document.querySelector(`[data-addon-id="${addonId}"]`);
   // Verify this add-on isn't installed yet.
   ok(!addonEl, "Addon is not installed yet");
 

devtools/client/aboutdebugging/test/browser_addons_reload.js

@@ -82,7 +82,7 @@ add_task(async function reloadButtonReloadsAddon() {
     }, ADDON_NAME);
   });
 
-  let reloaded = once(AboutDebugging, "addon-reload");
+  const reloaded = once(AboutDebugging, "addon-reload");
   reloadButton.click();
   await reloaded;
 
@@ -129,7 +129,7 @@ add_task(async function reloadButtonRefreshesMetadata() {
   // Wait for the add-on list to be updated with the reloaded name.
   const onReInstall = promiseAddonEvent("onInstalled");
   const reloadButton = getReloadButton(document, manifestBase.name);
-  let reloaded = once(AboutDebugging, "addon-reload");
+  const reloaded = once(AboutDebugging, "addon-reload");
   reloadButton.click();
   await reloaded;
 

devtools/client/aboutdebugging/test/browser_addons_toggle_debug.js

@@ -12,14 +12,14 @@ const ADDON_NAME = "test-devtools";
 add_task(async function() {
   info("Turn off addon debugging.");
   await new Promise(resolve => {
-    let options = {"set": [
+    const options = {"set": [
       ["devtools.chrome.enabled", false],
       ["devtools.debugger.remote-enabled", false],
     ]};
     SpecialPowers.pushPrefEnv(options, resolve);
   });
 
-  let { tab, document } = await openAboutDebugging("addons");
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   info("Install a test addon.");
@@ -29,11 +29,11 @@ add_task(async function() {
     name: ADDON_NAME,
   });
 
-  let addonDebugCheckbox = document.querySelector("#enable-addon-debugging");
+  const addonDebugCheckbox = document.querySelector("#enable-addon-debugging");
   ok(!addonDebugCheckbox.checked, "Addons debugging should be disabled.");
 
   info("Check all debug buttons are disabled.");
-  let debugButtons = [...document.querySelectorAll("#addons .debug-button")];
+  const debugButtons = [...document.querySelectorAll("#addons .debug-button")];
   ok(debugButtons.every(b => b.disabled), "Debug buttons should be disabled");
 
   info("Click on 'Enable addons debugging' checkbox.");

devtools/client/aboutdebugging/test/browser_page_not_found.js

@@ -7,7 +7,7 @@
 // Every url navigating including #invalid-hash should be kept in history and
 // navigate back as expected.
 add_task(async function() {
-  let { tab, document } = await openAboutDebugging("invalid-hash");
+  const { tab, document } = await openAboutDebugging("invalid-hash");
   let element = document.querySelector(".header-name");
   is(element.textContent, "Page not found", "Show error page");
 

devtools/client/aboutdebugging/test/browser_service_workers.js

@@ -11,11 +11,11 @@ const TAB_URL = URL_ROOT + "service-workers/empty-sw.html";
 add_task(async function() {
   await enableServiceWorkerDebugging();
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
   await waitUntil(() => {
     // Check that the service worker appears in the UI

devtools/client/aboutdebugging/test/browser_service_workers_fetch_flag.js

@@ -10,11 +10,11 @@ const FETCH_SW_TAB_URL = URL_ROOT + "service-workers/fetch-sw.html";
 
 async function testBody(url, expecting) {
   await enableServiceWorkerDebugging();
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
-  let swTab = await addTab(url);
+  const swTab = await addTab(url);
 
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
   info("Wait for fetch flag.");
   await waitUntil(() => {

devtools/client/aboutdebugging/test/browser_service_workers_multi_content_process.js

@@ -15,19 +15,19 @@ add_task(async function() {
   info("Force two content processes");
   await pushPref("dom.ipc.processCount", 2);
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
-  let warningSection = document.querySelector(".service-worker-multi-process");
-  let img = warningSection.querySelector(".warning");
+  const warningSection = document.querySelector(".service-worker-multi-process");
+  const img = warningSection.querySelector(".warning");
   ok(img, "warning message is rendered");
 
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
-  let swTab = await addTab(TAB_URL, { background: true });
+  const swTab = await addTab(TAB_URL, { background: true });
 
   info("Wait for service worker to appear in the list");
   // Check that the service worker appears in the UI
-  let serviceWorkerContainer =
+  const serviceWorkerContainer =
     await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
 
   info("Wait until the service worker is running and the Debug button appears");
@@ -40,8 +40,8 @@ add_task(async function() {
   ok(debugButton.disabled, "Start/Debug button is disabled");
 
   info("Update the preference to 1");
-  let onWarningCleared = waitUntil(() => {
-    let hasWarning = document.querySelector(".service-worker-multi-process");
+  const onWarningCleared = waitUntil(() => {
+    const hasWarning = document.querySelector(".service-worker-multi-process");
     return !hasWarning && !debugButton.disabled;
   }, 100);
   await pushPref("dom.ipc.processCount", 1);
@@ -49,8 +49,8 @@ add_task(async function() {
   ok(!debugButton.disabled, "Debug button is enabled.");
 
   info("Update the preference back to 2");
-  let onWarningRestored = waitUntil(() => {
-    let hasWarning = document.querySelector(".service-worker-multi-process");
+  const onWarningRestored = waitUntil(() => {
+    const hasWarning = document.querySelector(".service-worker-multi-process");
     return hasWarning && getDebugButton(serviceWorkerContainer).disabled;
   }, 100);
   await pushPref("dom.ipc.processCount", 2);

devtools/client/aboutdebugging/test/browser_service_workers_not_compatible.js

@@ -14,15 +14,15 @@ var imgClass = ".service-worker-disabled .warning";
 add_task(async function() {
   await new Promise(done => {
     info("disable service workers");
-    let options = {"set": [
+    const options = {"set": [
       ["dom.serviceWorkers.enabled", false],
     ]};
     SpecialPowers.pushPrefEnv(options, done);
   });
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
   // Check that the warning img appears in the UI
-  let img = document.querySelector(imgClass);
+  const img = document.querySelector(imgClass);
   ok(img, "warning message is rendered");
 
   await closeAboutDebugging(tab);
@@ -31,15 +31,15 @@ add_task(async function() {
 add_task(async function() {
   await new Promise(done => {
     info("set private browsing mode as default");
-    let options = {"set": [
+    const options = {"set": [
       ["browser.privatebrowsing.autostart", true],
     ]};
     SpecialPowers.pushPrefEnv(options, done);
   });
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
   // Check that the warning img appears in the UI
-  let img = document.querySelector(imgClass);
+  const img = document.querySelector(imgClass);
   ok(img, "warning message is rendered");
 
   await closeAboutDebugging(tab);
@@ -47,12 +47,12 @@ add_task(async function() {
 
 add_task(async function() {
   info("Opening a new private window");
-  let win = OpenBrowserWindow({private: true});
+  const win = OpenBrowserWindow({private: true});
   await waitForDelayedStartupFinished(win);
 
-  let { tab, document } = await openAboutDebugging("workers", win);
+  const { tab, document } = await openAboutDebugging("workers", win);
   // Check that the warning img appears in the UI
-  let img = document.querySelector(imgClass);
+  const img = document.querySelector(imgClass);
   ok(img, "warning message is rendered");
 
   await closeAboutDebugging(tab);

devtools/client/aboutdebugging/test/browser_service_workers_push.js

@@ -16,25 +16,25 @@ const TAB_URL = URL_ROOT + "service-workers/push-sw.html";
 
 add_task(async function() {
   await enableServiceWorkerDebugging();
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
   // Listen for mutations in the service-workers list.
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
   // Open a tab that registers a push service worker.
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   info("Make the test page notify us when the service worker sends a message.");
 
   await ContentTask.spawn(swTab.linkedBrowser, {}, function() {
-    let win = content.wrappedJSObject;
+    const win = content.wrappedJSObject;
     win.navigator.serviceWorker.addEventListener("message", function(event) {
       sendAsyncMessage(event.data);
     });
   });
 
   // Expect the service worker to claim the test window when activating.
-  let onClaimed = onTabMessage(swTab, "sw-claimed");
+  const onClaimed = onTabMessage(swTab, "sw-claimed");
 
   info("Wait until the service worker appears in the UI");
   await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
@@ -47,13 +47,13 @@ add_task(async function() {
   await waitForServiceWorkerActivation(SERVICE_WORKER, document);
 
   // Retrieve the Push button for the worker.
-  let names = [...document.querySelectorAll("#service-workers .target-name")];
-  let name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
+  const names = [...document.querySelectorAll("#service-workers .target-name")];
+  const name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
   ok(name, "Found the service worker in the list");
 
-  let targetElement = name.parentNode.parentNode;
+  const targetElement = name.parentNode.parentNode;
 
-  let pushBtn = targetElement.querySelector(".push-button");
+  const pushBtn = targetElement.querySelector(".push-button");
   ok(pushBtn, "Found its push button");
 
   info("Wait for the service worker to claim the test window before proceeding.");
@@ -61,7 +61,7 @@ add_task(async function() {
 
   info("Click on the Push button and wait for the service worker to receive " +
     "a push notification");
-  let onPushNotification = onTabMessage(swTab, "sw-pushed");
+  const onPushNotification = onTabMessage(swTab, "sw-pushed");
 
   pushBtn.click();
   await onPushNotification;
@@ -83,7 +83,7 @@ add_task(async function() {
  * Helper to listen once on a message sent using postMessage from the provided tab.
  */
 function onTabMessage(tab, message) {
-  let mm = tab.linkedBrowser.messageManager;
+  const mm = tab.linkedBrowser.messageManager;
   return new Promise(done => {
     mm.addMessageListener(message, function listener() {
       mm.removeMessageListener(message, listener);

devtools/client/aboutdebugging/test/browser_service_workers_push_service.js

@@ -33,7 +33,7 @@ add_task(async function() {
     },
     init() {},
     register(pageRecord) {
-      let registration = {
+      const registration = {
         endpoint: FAKE_ENDPOINT
       };
       this._registrations.set(pageRecord.scope, registration);
@@ -44,7 +44,7 @@ add_task(async function() {
       return Promise.resolve(this._registrations.get(pageRecord.scope));
     },
     unregister(pageRecord) {
-      let deleted = this._registrations.delete(pageRecord.scope);
+      const deleted = this._registrations.delete(pageRecord.scope);
       if (deleted) {
         this._notify(pageRecord.scope);
       }
@@ -52,13 +52,13 @@ add_task(async function() {
     },
   };
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
   // Listen for mutations in the service-workers list.
-  let serviceWorkersElement = document.getElementById("service-workers");
+  const serviceWorkersElement = document.getElementById("service-workers");
 
   // Open a tab that registers a push service worker.
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   info("Wait until the service worker appears in about:debugging");
   await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
@@ -66,22 +66,22 @@ add_task(async function() {
   await waitForServiceWorkerActivation(SERVICE_WORKER, document);
 
   // Wait for the service worker details to update.
-  let names = [...document.querySelectorAll("#service-workers .target-name")];
-  let name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
+  const names = [...document.querySelectorAll("#service-workers .target-name")];
+  const name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
   ok(name, "Found the service worker in the list");
 
-  let targetContainer = name.closest(".target-container");
+  const targetContainer = name.closest(".target-container");
 
   // Retrieve the push subscription endpoint URL, and verify it looks good.
   info("Wait for the push URL");
-  let pushURL = await waitUntilElement(".service-worker-push-url", targetContainer);
+  const pushURL = await waitUntilElement(".service-worker-push-url", targetContainer);
 
   info("Found the push service URL in the service worker details");
   is(pushURL.textContent, FAKE_ENDPOINT, "The push service URL looks correct");
 
   // Unsubscribe from the push service.
   ContentTask.spawn(swTab.linkedBrowser, {}, function() {
-    let win = content.wrappedJSObject;
+    const win = content.wrappedJSObject;
     return win.sub.unsubscribe();
   });
 

devtools/client/aboutdebugging/test/browser_service_workers_start.js

@@ -19,13 +19,13 @@ add_task(async function() {
   await pushPref("dom.serviceWorkers.idle_timeout", SW_TIMEOUT);
   await pushPref("dom.serviceWorkers.idle_extended_timeout", SW_TIMEOUT);
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
   // Listen for mutations in the service-workers list.
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
   // Open a tab that registers an empty service worker.
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   // Wait for the service-workers list to update.
   info("Wait until the service worker appears in about:debugging");
@@ -39,10 +39,10 @@ add_task(async function() {
   await waitForServiceWorkerActivation(SERVICE_WORKER, document);
 
   // Retrieve the Target element corresponding to the service worker.
-  let names = [...document.querySelectorAll("#service-workers .target-name")];
-  let name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
+  const names = [...document.querySelectorAll("#service-workers .target-name")];
+  const name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
   ok(name, "Found the service worker in the list");
-  let targetElement = name.parentNode.parentNode;
+  const targetElement = name.parentNode.parentNode;
 
   // The service worker may already be killed with the low 1s timeout.
   // At this stage, either the SW is started and the Debug button is visible or was
@@ -52,7 +52,7 @@ add_task(async function() {
   await waitUntilElement(".start-button", targetElement);
 
   // We should now have a Start button but no Debug button.
-  let startBtn = targetElement.querySelector(".start-button");
+  const startBtn = targetElement.querySelector(".start-button");
   ok(startBtn, "Found its start button");
   ok(!targetElement.querySelector(".debug-button"), "No debug button");
 

devtools/client/aboutdebugging/test/browser_service_workers_status.js

@@ -16,21 +16,21 @@ add_task(async function() {
   await pushPref("dom.serviceWorkers.idle_timeout", SW_TIMEOUT);
   await pushPref("dom.serviceWorkers.idle_extended_timeout", SW_TIMEOUT);
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
   // Listen for mutations in the service-workers list.
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   info("Wait until the service worker appears in about:debugging");
-  let container = await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
+  const container = await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
 
   // We should ideally check that the service worker registration goes through the
   // "registering" and "running" steps, but it is difficult to workaround race conditions
   // for a test running on a wide variety of platforms. Due to intermittent failures, we
   // simply check that the registration transitions to "stopped".
-  let status = container.querySelector(".target-status");
+  const status = container.querySelector(".target-status");
   await waitUntil(() => status.textContent == "Stopped", 100);
   is(status.textContent, "Stopped", "Service worker is currently stopped");
 

devtools/client/aboutdebugging/test/browser_service_workers_timeout.js

@@ -16,11 +16,11 @@ add_task(async function() {
   await pushPref("dom.serviceWorkers.idle_timeout", SW_TIMEOUT);
   await pushPref("dom.serviceWorkers.idle_extended_timeout", SW_TIMEOUT);
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
-  let serviceWorkersElement = getServiceWorkerList(document);
+  const serviceWorkersElement = getServiceWorkerList(document);
 
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   info("Wait until the service worker appears in about:debugging");
   await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
@@ -30,15 +30,15 @@ add_task(async function() {
   ok(true, "Service worker registration resolved");
 
   // Retrieve the DEBUG button for the worker
-  let names = [...document.querySelectorAll("#service-workers .target-name")];
-  let name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
+  const names = [...document.querySelectorAll("#service-workers .target-name")];
+  const name = names.filter(element => element.textContent === SERVICE_WORKER)[0];
   ok(name, "Found the service worker in the list");
-  let targetElement = name.parentNode.parentNode;
-  let debugBtn = targetElement.querySelector(".debug-button");
+  const targetElement = name.parentNode.parentNode;
+  const debugBtn = targetElement.querySelector(".debug-button");
   ok(debugBtn, "Found its debug button");
 
   // Click on it and wait for the toolbox to be ready
-  let onToolboxReady = new Promise(done => {
+  const onToolboxReady = new Promise(done => {
     gDevTools.once("toolbox-ready", function(toolbox) {
       done(toolbox);
     });

devtools/client/aboutdebugging/test/browser_service_workers_unregister.js

@@ -17,10 +17,10 @@ const TAB_URL = SCOPE + "empty-sw.html";
 add_task(async function() {
   await enableServiceWorkerDebugging();
 
-  let { tab, document } = await openAboutDebugging("workers");
+  const { tab, document } = await openAboutDebugging("workers");
 
   // Open a tab that registers an empty service worker.
-  let swTab = await addTab(TAB_URL);
+  const swTab = await addTab(TAB_URL);
 
   info("Wait until the service worker appears in about:debugging");
   await waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
@@ -32,20 +32,20 @@ add_task(async function() {
   await waitForServiceWorkerRegistered(swTab);
   ok(true, "Service worker registration resolved");
 
-  let targets = document.querySelectorAll("#service-workers .target");
+  const targets = document.querySelectorAll("#service-workers .target");
   is(targets.length, 1, "One service worker is now displayed.");
 
-  let target = targets[0];
-  let name = target.querySelector(".target-name");
+  const target = targets[0];
+  const name = target.querySelector(".target-name");
   is(name.textContent, SERVICE_WORKER, "Found the service worker in the list");
 
   info("Check the scope displayed scope is correct");
-  let scope = target.querySelector(".service-worker-scope");
+  const scope = target.querySelector(".service-worker-scope");
   is(scope.textContent, SCOPE,
     "The expected scope is displayed in the service worker info.");
 
   info("Unregister the service worker via the unregister link.");
-  let unregisterLink = target.querySelector(".unregister-link");
+  const unregisterLink = target.querySelector(".unregister-link");
   ok(unregisterLink, "Found the unregister link");
 
   unregisterLink.click();

devtools/client/aboutdebugging/test/browser_tabs.js

@@ -6,7 +6,7 @@
 const TAB_URL = "data:text/html,<title>foo</title>";
 
 add_task(async function() {
-  let { tab, document } = await openAboutDebugging("tabs");
+  const { tab, document } = await openAboutDebugging("tabs");
 
   // Wait for initial tabs list which may be empty
   let tabsElement = getTabList(document);
@@ -16,25 +16,25 @@ add_task(async function() {
   tabsElement = getTabList(document);
 
   let names = [...tabsElement.querySelectorAll(".target-name")];
-  let initialTabCount = names.length;
+  const initialTabCount = names.length;
 
   info("Open a new background tab");
-  let newTab = await addTab(TAB_URL, { background: true });
+  const newTab = await addTab(TAB_URL, { background: true });
 
   info("Wait for the tab to appear in the list with the correct name");
-  let container = await waitUntilTabContainer("foo", document);
+  const container = await waitUntilTabContainer("foo", document);
 
   info("Wait until the title to update");
   await waitUntil(() => {
     return container.querySelector(".target-name").title === TAB_URL;
   }, 100);
 
-  let icon = container.querySelector(".target-icon");
+  const icon = container.querySelector(".target-icon");
   ok(icon && icon.src, "Tab icon found and src attribute is not empty");
 
   info("Check if the tab icon is a valid image");
   await new Promise(r => {
-    let image = new Image();
+    const image = new Image();
     image.onload = () => {
       ok(true, "Favicon is not a broken image");
       r();
@@ -60,8 +60,8 @@ add_task(async function() {
 });
 
 function getTabContainer(name, document) {
-  let nameElements = [...document.querySelectorAll("#tabs .target-name")];
-  let nameElement = nameElements.filter(element => element.textContent === name)[0];
+  const nameElements = [...document.querySelectorAll("#tabs .target-name")];
+  const nameElement = nameElements.filter(element => element.textContent === name)[0];
   if (nameElement) {
     return nameElement.closest(".target-container");
   }

devtools/client/aboutdebugging/test/head.js

@@ -22,10 +22,10 @@ async function openAboutDebugging(page, win) {
     url += "#" + page;
   }
 
-  let tab = await addTab(url, { window: win });
-  let browser = tab.linkedBrowser;
-  let document = browser.contentDocument;
-  let window = browser.contentWindow;
+  const tab = await addTab(url, { window: win });
+  const browser = tab.linkedBrowser;
+  const document = browser.contentDocument;
+  const window = browser.contentWindow;
 
   info("Wait until the main about debugging container is available");
   await waitUntilElement(".app", document);
@@ -39,10 +39,10 @@ function closeAboutDebugging(tab) {
 }
 
 function getSupportsFile(path) {
-  let cr = Cc["@mozilla.org/chrome/chrome-registry;1"]
+  const cr = Cc["@mozilla.org/chrome/chrome-registry;1"]
     .getService(Ci.nsIChromeRegistry);
-  let uri = Services.io.newURI(CHROME_URL_ROOT + path);
-  let fileurl = cr.convertChromeURL(uri);
+  const uri = Services.io.newURI(CHROME_URL_ROOT + path);
+  const fileurl = cr.convertChromeURL(uri);
   return fileurl.QueryInterface(Ci.nsIFileURL);
 }
 
@@ -110,8 +110,8 @@ function getServiceWorkerList(document) {
  * @return {DOMNode} container element
  */
 function getServiceWorkerContainer(name, document) {
-  let nameElements = [...document.querySelectorAll("#service-workers .target-name")];
-  let nameElement = nameElements.filter(element => element.textContent === name)[0];
+  const nameElements = [...document.querySelectorAll("#service-workers .target-name")];
+  const nameElement = nameElements.filter(element => element.textContent === name)[0];
   if (nameElement) {
     return nameElement.closest(".target-container");
   }
@@ -167,9 +167,9 @@ function getTabList(document) {
 
 async function installAddon({document, path, name, isWebExtension}) {
   // Mock the file picker to select a test addon
-  let MockFilePicker = SpecialPowers.MockFilePicker;
+  const MockFilePicker = SpecialPowers.MockFilePicker;
   MockFilePicker.init(window);
-  let file = getSupportsFile(path);
+  const file = getSupportsFile(path);
   MockFilePicker.setFiles([file.file]);
 
   let onAddonInstalled;
@@ -208,8 +208,8 @@ async function installAddon({document, path, name, isWebExtension}) {
 async function uninstallAddon({document, id, name}) {
   // Now uninstall this addon
   await new Promise(async done => {
-    let addon = await AddonManager.getAddonByID(id);
-    let listener = {
+    const addon = await AddonManager.getAddonByID(id);
+    const listener = {
       onUninstalled: function(uninstalledAddon) {
         if (uninstalledAddon != addon) {
           return;
@@ -229,7 +229,7 @@ async function uninstallAddon({document, id, name}) {
 
 function getAddonCount(document) {
   const addonListContainer = getAddonList(document);
-  let addonElements = addonListContainer.querySelectorAll(".target");
+  const addonElements = addonListContainer.querySelectorAll(".target");
   return addonElements.length;
 }
 
@@ -245,8 +245,8 @@ function waitForInitialAddonList(document) {
 }
 
 function getAddonContainer(name, document) {
-  let nameElements = [...document.querySelectorAll("#addons-panel .target-name")];
-  let nameElement = nameElements.filter(element => element.textContent === name)[0];
+  const nameElements = [...document.querySelectorAll("#addons-panel .target-name")];
+  const nameElement = nameElements.filter(element => element.textContent === name)[0];
   if (nameElement) {
     return nameElement.closest(".addon-target-container");
   }
@@ -285,7 +285,7 @@ function assertHasTarget(expected, document, type, name) {
 function waitForServiceWorkerRegistered(tab) {
   return ContentTask.spawn(tab.linkedBrowser, {}, async function() {
     // Retrieve the `sw` promise created in the html page.
-    let { sw } = content.wrappedJSObject;
+    const { sw } = content.wrappedJSObject;
     await sw;
   });
 }
@@ -302,10 +302,10 @@ function waitForServiceWorkerRegistered(tab) {
 async function unregisterServiceWorker(tab, serviceWorkersElement) {
   // Get the initial count of service worker registrations.
   let registrations = serviceWorkersElement.querySelectorAll(".target-container");
-  let registrationCount = registrations.length;
+  const registrationCount = registrations.length;
 
   // Wait until the registration count is decreased by one.
-  let isRemoved = waitUntil(() => {
+  const isRemoved = waitUntil(() => {
     registrations = serviceWorkersElement.querySelectorAll(".target-container");
     return registrations.length === registrationCount - 1;
   }, 100);
@@ -313,8 +313,8 @@ async function unregisterServiceWorker(tab, serviceWorkersElement) {
   // Unregister the service worker from the content page
   await ContentTask.spawn(tab.linkedBrowser, {}, async function() {
     // Retrieve the `sw` promise created in the html page
-    let { sw } = content.wrappedJSObject;
-    let registration = await sw;
+    const { sw } = content.wrappedJSObject;
+    const registration = await sw;
     await registration.unregister();
   });
 
@@ -343,7 +343,7 @@ function waitForDelayedStartupFinished(win) {
  */
 async function setupTestAboutDebuggingWebExtension(name, path) {
   await new Promise(resolve => {
-    let options = {"set": [
+    const options = {"set": [
       // Force enabling of addons debugging
       ["devtools.chrome.enabled", true],
       ["devtools.debugger.remote-enabled", true],
@@ -355,7 +355,7 @@ async function setupTestAboutDebuggingWebExtension(name, path) {
     SpecialPowers.pushPrefEnv(options, resolve);
   });
 
-  let { tab, document } = await openAboutDebugging("addons");
+  const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 
   await installAddon({
@@ -366,11 +366,11 @@ async function setupTestAboutDebuggingWebExtension(name, path) {
   });
 
   // Retrieve the DEBUG button for the addon
-  let names = getInstalledAddonNames(document);
-  let nameEl = names.filter(element => element.textContent === name)[0];
+  const names = getInstalledAddonNames(document);
+  const nameEl = names.filter(element => element.textContent === name)[0];
   ok(name, "Found the addon in the list");
-  let targetElement = nameEl.parentNode.parentNode;
-  let debugBtn = targetElement.querySelector(".debug-button");
+  const targetElement = nameEl.parentNode.parentNode;
+  const debugBtn = targetElement.querySelector(".debug-button");
   ok(debugBtn, "Found its debug button");
 
   return { tab, document, debugBtn };
@@ -381,12 +381,12 @@ async function setupTestAboutDebuggingWebExtension(name, path) {
  * corresponding to the provided service worker url.
  */
 async function waitForServiceWorkerActivation(swUrl, document) {
-  let serviceWorkersElement = getServiceWorkerList(document);
-  let names = serviceWorkersElement.querySelectorAll(".target-name");
-  let name = [...names].filter(element => element.textContent === swUrl)[0];
+  const serviceWorkersElement = getServiceWorkerList(document);
+  const names = serviceWorkersElement.querySelectorAll(".target-name");
+  const name = [...names].filter(element => element.textContent === swUrl)[0];
 
-  let targetElement = name.parentNode.parentNode;
-  let targetStatus = targetElement.querySelector(".target-status");
+  const targetElement = name.parentNode.parentNode;
+  const targetStatus = targetElement.querySelector(".target-status");
   await waitUntil(() => {
     return targetStatus.textContent !== "Registering";
   }, 100);
@@ -396,7 +396,7 @@ async function waitForServiceWorkerActivation(swUrl, document) {
  * Set all preferences needed to enable service worker debugging and testing.
  */
 async function enableServiceWorkerDebugging() {
-  let options = { "set": [
+  const options = { "set": [
     // Enable service workers.
     ["dom.serviceWorkers.enabled", true],
     // Accept workers from mochitest's http.
@@ -419,7 +419,7 @@ async function enableServiceWorkerDebugging() {
  */
 function promiseAddonEvent(event) {
   return new Promise(resolve => {
-    let listener = {
+    const listener = {
       [event]: function(...args) {
         AddonManager.removeAddonListener(listener);
         resolve(args);
@@ -435,7 +435,7 @@ function promiseAddonEvent(event) {
  */
 function installAddonWithManager(filePath) {
   return new Promise(async (resolve, reject) => {
-    let install = await AddonManager.getInstallForFile(filePath);
+    const install = await AddonManager.getInstallForFile(filePath);
     if (!install) {
       throw new Error(`An install was not created for ${filePath}`);
     }

devtools/client/aboutdebugging/test/service-workers/push-sw.html

@@ -15,14 +15,14 @@ var sub = null;
 // The registration promise is expected as a global by head.js's unregisterServiceWorker.
 var sw = (async function() {
   await new Promise(resolve => {
-    let perm = { type: "desktop-notification", allow: true, context: document };
+    const perm = { type: "desktop-notification", allow: true, context: document };
     SpecialPowers.pushPermissions([perm], resolve);
   });
 
-  let registrationPromise = navigator.serviceWorker.register("push-sw.js");
+  const registrationPromise = navigator.serviceWorker.register("push-sw.js");
 
   try {
-    let registration = await registrationPromise;
+    const registration = await registrationPromise;
     dump("SW registered\n");
 
     try {

devtools/client/accessibility/accessibility-view.js

@@ -82,7 +82,7 @@ AccessibilityView.prototype = {
     // point.
     if (!accessible || accessible.indexInParent < 0) {
       const { nodes: children } = await gToolbox.walker.children(node);
-      for (let child of children) {
+      for (const child of children) {
         if (child.nodeType === nodeConstants.TEXT_NODE) {
           accessible = await walker.getAccessibleFor(child);
           if (accessible && accessible.indexInParent >= 0) {

devtools/client/accessibility/components/AccessibilityTree.js

@@ -50,7 +50,7 @@ class AccessibilityTree extends Component {
    * and updates.
    */
   componentWillMount() {
-    let { walker } = this.props;
+    const { walker } = this.props;
     walker.on("reorder", this.onReorder);
     walker.on("name-change", this.onNameChange);
     walker.on("text-change", this.onTextChange);
@@ -65,7 +65,7 @@ class AccessibilityTree extends Component {
    * Remove accessible walker front event listeners.
    */
   componentWillUnmount() {
-    let { walker } = this.props;
+    const { walker } = this.props;
     walker.off("reorder", this.onReorder);
     walker.off("name-change", this.onNameChange);
     walker.off("text-change", this.onTextChange);
@@ -95,7 +95,7 @@ class AccessibilityTree extends Component {
    *                            accessible walker as a parent.
    */
   onNameChange(accessible, parent) {
-    let { accessibles, walker, dispatch } = this.props;
+    const { accessibles, walker, dispatch } = this.props;
     parent = parent || walker;
 
     if (accessibles.has(accessible.actorID) ||
@@ -113,7 +113,7 @@ class AccessibilityTree extends Component {
    *                              changed.
    */
   onTextChange(accessible) {
-    let { accessibles, dispatch } = this.props;
+    const { accessibles, dispatch } = this.props;
     if (accessibles.has(accessible.actorID)) {
       dispatch(fetchChildren(accessible));
     }
@@ -123,7 +123,7 @@ class AccessibilityTree extends Component {
    * Render Accessibility panel content
    */
   render() {
-    let columns = [{
+    const columns = [{
       "id": "default",
       "title": L10N.getStr("accessibility.role")
     }, {
@@ -131,7 +131,7 @@ class AccessibilityTree extends Component {
       "title": L10N.getStr("accessibility.name")
     }];
 
-    let {
+    const {
       accessibles,
       dispatch,
       expanded,
@@ -140,16 +140,16 @@ class AccessibilityTree extends Component {
       walker
     } = this.props;
 
-    let renderValue = props => {
+    const renderValue = props => {
       return Rep(Object.assign({}, props, {
         defaultRep: Grip,
         cropLimit: 50,
       }));
     };
 
-    let renderRow = rowProps => {
-      let { object } = rowProps.member;
-      let highlighted = object === highlightedItem;
+    const renderRow = rowProps => {
+      const { object } = rowProps.member;
+      const highlighted = object === highlightedItem;
       return AccessibilityRow(Object.assign({}, rowProps, {
         walker,
         highlighted,

devtools/client/accessibility/components/Accessible.js

@@ -37,7 +37,7 @@ class AccessiblePropertyClass extends Component {
   }
 
   componentDidUpdate({ object: prevObject, accessible: prevAccessible }) {
-    let { accessible, object, focused } = this.props;
+    const { accessible, object, focused } = this.props;
     // Fast check if row is focused or if the value did not update.
     if (focused || accessible !== prevAccessible || prevObject === object ||
         (object && prevObject && typeof object === "object")) {
@@ -48,7 +48,7 @@ class AccessiblePropertyClass extends Component {
   }
 
   flashRow() {
-    let row = findDOMNode(this);
+    const row = findDOMNode(this);
     flashElementOn(row);
     if (this._flashMutationTimer) {
       clearTimeout(this._flashMutationTimer);
@@ -96,7 +96,7 @@ class Accessible extends Component {
   }
 
   componentWillReceiveProps({ accessible }) {
-    let oldAccessible = this.props.accessible;
+    const oldAccessible = this.props.accessible;
 
     if (oldAccessible) {
       if (accessible && accessible.actorID === oldAccessible.actorID) {
@@ -113,21 +113,21 @@ class Accessible extends Component {
   componentWillUnmount() {
     window.off(EVENTS.NEW_ACCESSIBLE_FRONT_INSPECTED, this.onAccessibleInspected);
 
-    let { accessible } = this.props;
+    const { accessible } = this.props;
     if (accessible) {
       ACCESSIBLE_EVENTS.forEach(event => accessible.off(event, this.update));
     }
   }
 
   onAccessibleInspected() {
-    let { props } = this.refs;
+    const { props } = this.refs;
     if (props) {
       props.refs.tree.focus();
     }
   }
 
   update() {
-    let { dispatch, accessible } = this.props;
+    const { dispatch, accessible } = this.props;
     if (gToolbox) {
       dispatch(updateDetails(gToolbox.walker, accessible));
     }
@@ -196,7 +196,7 @@ class Accessible extends Component {
 
   renderItem(item, depth, focused, arrow, expanded) {
     const object = item.contents;
-    let valueProps = {
+    const valueProps = {
       object,
       mode: MODE.TINY,
       title: "Object",
@@ -210,7 +210,7 @@ class Accessible extends Component {
       valueProps.onInspectIconClick = () => this.selectNode(this.props.DOMNode);
     }
 
-    let classList = [ "node", "object-node" ];
+    const classList = [ "node", "object-node" ];
     if (focused) {
       classList.push("focused");
     }
@@ -278,11 +278,11 @@ class Accessible extends Component {
  * @return {Object?}        Possibly found focused item.
  */
 const findFocused = (focused, items) => {
-  for (let item of items) {
+  for (const item of items) {
     if (item.path === focused) {
       return item;
     }
-    let found = findFocused(focused, item.children);
+    const found = findFocused(focused, item.children);
     if (found) {
       return found;
     }
@@ -306,12 +306,12 @@ const isNode = value => value && value.typeName === "domnode";
  * @returns {Object} a grip-like object that can be used with Reps.
  */
 const translateNodeFrontToGrip = nodeFront => {
-  let { attributes, actorID, typeName, nodeName, nodeType } = nodeFront;
+  const { attributes, actorID, typeName, nodeName, nodeType } = nodeFront;
 
   // The main difference between NodeFront and grips is that attributes are treated as
   // a map in grips and as an array in NodeFronts.
-  let attributesMap = {};
-  for (let { name, value } of attributes) {
+  const attributesMap = {};
+  for (const { name, value } of attributes) {
     attributesMap[name] = value;
   }
 
@@ -339,7 +339,7 @@ const translateNodeFrontToGrip = nodeFront => {
 const makeItemsForDetails = (props, parentPath) =>
   Object.getOwnPropertyNames(props).map(name => {
     let children = [];
-    let path = `${parentPath}/${name}`;
+    const path = `${parentPath}/${name}`;
     let contents = props[name];
 
     if (contents) {
@@ -370,16 +370,16 @@ const makeParentMap = (items) => {
 };
 
 const mapStateToProps = ({ details }) => {
-  let { accessible, DOMNode } = details;
+  const { accessible, DOMNode } = details;
   if (!accessible || !DOMNode) {
     return {};
   }
 
-  let items = makeItemsForDetails(ORDERED_PROPS.reduce((props, key) => {
+  const items = makeItemsForDetails(ORDERED_PROPS.reduce((props, key) => {
     props[key] = key === "DOMNode" ? DOMNode : accessible[key];
     return props;
   }, {}), "");
-  let parents = makeParentMap(items);
+  const parents = makeParentMap(items);
 
   return { accessible, DOMNode, items, parents };
 };

devtools/client/accessibility/components/Button.js

@@ -38,16 +38,16 @@ class Button extends Component {
   }
 
   render() {
-    let className = [
+    const className = [
       ...this.props.className.split(" "),
       "devtools-button"
     ].join(" ");
-    let props = Object.assign({}, this.props, {
+    const props = Object.assign({}, this.props, {
       className,
       "aria-busy": this.props.busy
     });
 
-    let classList = ["btn-content"];
+    const classList = ["btn-content"];
     if (this.props.busy) {
       classList.push("devtools-throbber");
     }

devtools/client/accessibility/components/Description.js

@@ -67,7 +67,7 @@ class Description extends Component {
   }
 
   onEnable() {
-    let { accessibility, dispatch } = this.props;
+    const { accessibility, dispatch } = this.props;
     this.setState({ enabling: true });
 
     if (gTelemetry) {
@@ -84,9 +84,9 @@ class Description extends Component {
   }
 
   render() {
-    let { canBeEnabled } = this.props;
-    let { enabling } = this.state;
-    let enableButtonStr = enabling ? "accessibility.enabling" : "accessibility.enable";
+    const { canBeEnabled } = this.props;
+    const { enabling } = this.state;
+    const enableButtonStr = enabling ? "accessibility.enabling" : "accessibility.enable";
 
     let title;
     let disableButton = false;

devtools/client/accessibility/components/MainFrame.js

@@ -68,12 +68,12 @@ class MainFrame extends Component {
   }
 
   resetAccessibility() {
-    let { dispatch, accessibility } = this.props;
+    const { dispatch, accessibility } = this.props;
     dispatch(reset(accessibility));
   }
 
   get useLandscapeMode() {
-    let { clientWidth } = document.getElementById("content");
+    const { clientWidth } = document.getElementById("content");
     return clientWidth > PORTRAIT_MODE_WIDTH;
   }
 
@@ -91,7 +91,7 @@ class MainFrame extends Component {
    * Render Accessibility panel content
    */
   render() {
-    let { accessibility, walker, enabled } = this.props;
+    const { accessibility, walker, enabled } = this.props;
 
     if (!enabled) {
       return Description({ accessibility });

devtools/client/accessibility/components/Toolbar.js

@@ -48,7 +48,7 @@ class Toolbar extends Component {
   }
 
   onDisable() {
-    let { accessibility, dispatch } = this.props;
+    const { accessibility, dispatch } = this.props;
     this.setState({ disabling: true });
 
     dispatch(disable(accessibility))
@@ -57,9 +57,9 @@ class Toolbar extends Component {
   }
 
   render() {
-    let { canBeDisabled } = this.props;
-    let { disabling } = this.state;
-    let disableButtonStr = disabling ?
+    const { canBeDisabled } = this.props;
+    const { disabling } = this.state;
+    const disableButtonStr = disabling ?
       "accessibility.disabling" : "accessibility.disable";
     let title;
     let isDisabled = false;

devtools/client/accessibility/provider.js

@@ -30,7 +30,7 @@ class Provider {
       return [];
     }
 
-    let obj = this.accessibles.get(accessible.actorID);
+    const obj = this.accessibles.get(accessible.actorID);
     if (!obj || !obj.children) {
       return this.dispatch(fetchChildren(accessible));
     }

devtools/client/accessibility/reducers/accessibles.js

@@ -37,12 +37,12 @@ function accessibles(state = getInitialState(), action) {
  * @param {Object} accessible Accessible object to remove from cache.
  */
 function cleanupChild(cache, accessible) {
-  let cached = cache.get(accessible.actorID);
+  const cached = cache.get(accessible.actorID);
   if (!cached) {
     return;
   }
 
-  for (let child of cached.children) {
+  for (const child of cached.children) {
     cleanupChild(cache, child);
   }
 
@@ -58,7 +58,7 @@ function cleanupChild(cache, accessible) {
  * @param {Object} accessible Accessible object to test for staleness.
  */
 function staleChildren(cache, accessible) {
-  let cached = cache.get(accessible.actorID);
+  const cached = cache.get(accessible.actorID);
   if (!cached) {
     return false;
   }
@@ -67,11 +67,11 @@ function staleChildren(cache, accessible) {
 }
 
 function updateChildrenCache(cache, accessible, children) {
-  let { actorID } = accessible;
+  const { actorID } = accessible;
 
   if (cache.has(actorID)) {
-    let cached = cache.get(actorID);
-    for (let child of cached.children) {
+    const cached = cache.get(actorID);
+    for (const child of cached.children) {
       // If exhisting children cache includes an accessible that is not present
       // any more or if child accessible is stale remove it and all its children
       // from cache.
@@ -96,7 +96,7 @@ function updateChildrenCache(cache, accessible, children) {
  * @return {Object} updated state
  */
 function onReceiveChildren(cache, action) {
-  let { accessible, response: children, error } = action;
+  const { accessible, response: children, error } = action;
 
   if (error) {
     console.warn("Error fetching children", accessible, error);
@@ -107,14 +107,14 @@ function onReceiveChildren(cache, action) {
 }
 
 function onReceiveAncestry(cache, action) {
-  let { accessible: acc, response: ancestry, error } = action;
+  const { accessible: acc, response: ancestry, error } = action;
 
   if (error) {
     console.warn("Error fetching ancestry", acc, error);
     return cache;
   }
 
-  let newCache = new Map(cache);
+  const newCache = new Map(cache);
   ancestry.forEach(({ accessible, children }) =>
     updateChildrenCache(newCache, accessible, children));
 

devtools/client/accessibility/reducers/details.js

@@ -33,7 +33,7 @@ function details(state = getInitialState(), action) {
  * @return {Object}  updated state
  */
 function onUpdateDetails(state, action) {
-  let { accessible, response: DOMNode, error } = action;
+  const { accessible, response: DOMNode, error } = action;
   if (error) {
     console.warn("Error fetching DOMNode for accessible", accessible, error);
     return state;

devtools/client/accessibility/reducers/ui.js

@@ -76,8 +76,8 @@ function onUnhighlight(state) {
 }
 
 function updateExpandedNodes(state, ancestry) {
-  let expanded = new Set(state.expanded);
-  let path = ancestry.reduceRight((accPath, { accessible }) => {
+  const expanded = new Set(state.expanded);
+  const path = ancestry.reduceRight((accPath, { accessible }) => {
     accPath = TreeView.subPath(accPath, accessible.actorID);
     expanded.add(accPath);
     return accPath;
@@ -92,7 +92,7 @@ function onHighlight(state, { accessible, response: ancestry, error }) {
     return state;
   }
 
-  let { expanded } = updateExpandedNodes(state, ancestry);
+  const { expanded } = updateExpandedNodes(state, ancestry);
   return Object.assign({}, state, { expanded, highlighted: accessible });
 }
 
@@ -102,8 +102,8 @@ function onSelect(state, { accessible, response: ancestry, error }) {
     return state;
   }
 
-  let { path, expanded } = updateExpandedNodes(state, ancestry);
-  let selected = TreeView.subPath(path, accessible.actorID);
+  const { path, expanded } = updateExpandedNodes(state, ancestry);
+  const selected = TreeView.subPath(path, accessible.actorID);
 
   return Object.assign({}, state, { expanded, selected });
 }
@@ -135,7 +135,7 @@ function onCanBeEnabledChange(state, { canBeEnabled }) {
  * @return {Object}  updated state
  */
 function onReset(state, { accessibility }) {
-  let { enabled, canBeDisabled, canBeEnabled } = accessibility;
+  const { enabled, canBeDisabled, canBeEnabled } = accessibility;
   toggleHighlightTool(enabled);
   return Object.assign({}, state, { enabled, canBeDisabled, canBeEnabled });
 }

devtools/client/accessibility/test/browser/browser_accessibility_context_menu_browser.js

@@ -6,11 +6,11 @@
 const TEST_URI = "<h1 id=\"h1\">header</h1><p id=\"p\">paragraph</p>";
 
 add_task(async function testNoShowAccessibilityPropertiesContextMenu() {
-  let tab = await addTab(buildURL(TEST_URI));
-  let { linkedBrowser: browser } = tab;
+  const tab = await addTab(buildURL(TEST_URI));
+  const { linkedBrowser: browser } = tab;
 
-  let contextMenu = document.getElementById("contentAreaContextMenu");
-  let awaitPopupShown = BrowserTestUtils.waitForEvent(contextMenu, "popupshown");
+  const contextMenu = document.getElementById("contentAreaContextMenu");
+  const awaitPopupShown = BrowserTestUtils.waitForEvent(contextMenu, "popupshown");
   await BrowserTestUtils.synthesizeMouse("#h1", 0, 0, {
     type: "contextmenu",
     button: 2,
@@ -18,7 +18,7 @@ add_task(async function testNoShowAccessibilityPropertiesContextMenu() {
   }, browser);
   await awaitPopupShown;
 
-  let inspectA11YPropsItem = contextMenu.querySelector("#context-inspect-a11y");
+  const inspectA11YPropsItem = contextMenu.querySelector("#context-inspect-a11y");
   ok(inspectA11YPropsItem.hidden, "Accessibility tools are not enabled.");
   contextMenu.hidePopup();
   gBrowser.removeCurrentTab();
@@ -27,10 +27,10 @@ add_task(async function testNoShowAccessibilityPropertiesContextMenu() {
 addA11YPanelTask("Test show accessibility properties context menu in browser.",
   TEST_URI,
   async function({ panel, toolbox, browser }) {
-    let headerSelector = "#h1";
+    const headerSelector = "#h1";
 
-    let contextMenu = document.getElementById("contentAreaContextMenu");
-    let awaitPopupShown = BrowserTestUtils.waitForEvent(contextMenu, "popupshown");
+    const contextMenu = document.getElementById("contentAreaContextMenu");
+    const awaitPopupShown = BrowserTestUtils.waitForEvent(contextMenu, "popupshown");
     await BrowserTestUtils.synthesizeMouse(headerSelector, 0, 0, {
       type: "contextmenu",
       button: 2,
@@ -38,17 +38,17 @@ addA11YPanelTask("Test show accessibility properties context menu in browser.",
     }, browser);
     await awaitPopupShown;
 
-    let inspectA11YPropsItem = contextMenu.querySelector("#context-inspect-a11y");
+    const inspectA11YPropsItem = contextMenu.querySelector("#context-inspect-a11y");
 
     info("Triggering 'Inspect Accessibility Properties' and waiting for " +
          "accessibility panel to open");
     inspectA11YPropsItem.click();
     contextMenu.hidePopup();
 
-    let selected = await panel.once("new-accessible-front-selected");
-    let expectedSelectedNode = await getNodeFront(headerSelector,
+    const selected = await panel.once("new-accessible-front-selected");
+    const expectedSelectedNode = await getNodeFront(headerSelector,
                                                   toolbox.getPanel("inspector"));
-    let expectedSelected = await panel.walker.getAccessibleFor(expectedSelectedNode);
+    const expectedSelected = await panel.walker.getAccessibleFor(expectedSelectedNode);
     is(toolbox.getCurrentPanel(), panel, "Accessibility panel is currently selected");
     is(selected, expectedSelected, "Accessible front selected correctly");
   });

devtools/client/accessibility/test/browser/browser_accessibility_context_menu_inspector.js

@@ -20,19 +20,19 @@ async function openContextMenuForNode({ toolbox }, selector) {
   } else if (typeof selector === "string") {
     await selectNode(selector, inspector, "test");
   } else {
-    let updated = inspector.once("inspector-updated");
+    const updated = inspector.once("inspector-updated");
     inspector.selection.setNodeFront(selector, { reason: "test" });
     await updated;
   }
 
-  let menuUpdated = inspector.once("node-menu-updated");
-  let allMenuItems = openContextMenuAndGetAllItems(inspector);
+  const menuUpdated = inspector.once("node-menu-updated");
+  const allMenuItems = openContextMenuAndGetAllItems(inspector);
   await menuUpdated;
   return allMenuItems;
 }
 
 function checkShowA11YPropertiesNode(allMenuItems, disabled) {
-  let showA11YPropertiesNode = allMenuItems.find(item =>
+  const showA11YPropertiesNode = allMenuItems.find(item =>
     item.id === "node-menu-showaccessibilityproperties");
   ok(showA11YPropertiesNode,
     "the popup menu now has a show accessibility properties item");
@@ -45,15 +45,15 @@ async function checkAccessibleObjectSelection({ toolbox, panel }, menuItem, isTe
   const inspector = await toolbox.getPanel("inspector");
   info("Triggering 'Show Accessibility Properties' and waiting for " +
        "accessibility panel to open");
-  let panelSelected = toolbox.once("accessibility-selected");
-  let objectSelected = panel.once("new-accessible-front-selected");
+  const panelSelected = toolbox.once("accessibility-selected");
+  const objectSelected = panel.once("new-accessible-front-selected");
   menuItem.click();
   await panelSelected;
-  let selected = await objectSelected;
+  const selected = await objectSelected;
 
-  let expectedNode = isText ?
+  const expectedNode = isText ?
     inspector.selection.nodeFront.inlineTextChild : inspector.selection.nodeFront;
-  let expectedSelected = await panel.walker.getAccessibleFor(expectedNode);
+  const expectedSelected = await panel.walker.getAccessibleFor(expectedNode);
   is(selected, expectedSelected, "Accessible front selected correctly");
 }
 
@@ -74,9 +74,9 @@ addA11YPanelTask("Test show accessibility properties context menu.", TEST_URI,
     showA11YPropertiesNode = checkShowA11YPropertiesNode(allMenuItems, true);
 
     const inspector = env.toolbox.getPanel("inspector");
-    let span2 = await getNodeFront("#span-2", inspector);
+    const span2 = await getNodeFront("#span-2", inspector);
     await inspector.markup.expandNode(span2);
-    let { nodes } = await inspector.walker.children(span2);
+    const { nodes } = await inspector.walker.children(span2);
     allMenuItems = await openContextMenuForNode(env, nodes[0]);
     showA11YPropertiesNode = checkShowA11YPropertiesNode(allMenuItems, false);
     await checkAccessibleObjectSelection(env, showA11YPropertiesNode, false);

devtools/client/accessibility/test/browser/browser_accessibility_sidebar.js

@@ -48,8 +48,8 @@ const tests = [{
 }, {
   desc: "Append a new child to the document.",
   action: async ({ browser }) => ContentTask.spawn(browser, {}, () => {
-    let doc = content.document;
-    let button = doc.createElement("button");
+    const doc = content.document;
+    const button = doc.createElement("button");
     button.textContent = "Press Me!";
     doc.body.appendChild(button);
   }),

devtools/client/accessibility/test/browser/head.js

@@ -45,7 +45,7 @@ function shutdownA11y() {
   Cu.forceShrinkingGC();
 
   return new Promise(resolve => {
-    let observe = (subject, topic, data) => {
+    const observe = (subject, topic, data) => {
       if (data === "0") {
         Services.obs.removeObserver(observe, "a11y-init-or-shutdown");
         resolve();
@@ -77,11 +77,11 @@ const EXPANDABLE_PROPS = ["actions", "states", "attributes"];
 async function addTestTab(url) {
   info("Adding a new test tab with URL: '" + url + "'");
 
-  let tab = await addTab(url);
-  let panel = await initAccessibilityPanel(tab);
-  let win = panel.panelWin;
-  let doc = win.document;
-  let store = win.view.store;
+  const tab = await addTab(url);
+  const panel = await initAccessibilityPanel(tab);
+  const win = panel.panelWin;
+  const doc = win.document;
+  const store = win.view.store;
 
   EventUtils.sendMouseEvent({ type: "click" },
     doc.getElementById("accessibility-enable-button"), win);
@@ -110,10 +110,10 @@ async function addTestTab(url) {
  * cleanup function to make sure that the panel is still present.
  */
 async function disableAccessibilityInspector(env) {
-  let { doc, win, panel } = env;
+  const { doc, win, panel } = env;
   // Disable accessibility service through the panel and wait for the shutdown
   // event.
-  let shutdown = panel._front.once("shutdown");
+  const shutdown = panel._front.once("shutdown");
   EventUtils.sendMouseEvent({ type: "click" },
     doc.getElementById("accessibility-disable-button"), win);
   await shutdown;
@@ -128,8 +128,8 @@ async function disableAccessibilityInspector(env) {
  * @return a promise that is resolved once the panel is open.
  */
 async function initAccessibilityPanel(tab = gBrowser.selectedTab) {
-  let target = TargetFactory.forTab(tab);
-  let toolbox = await gDevTools.showToolbox(target, "accessibility");
+  const target = TargetFactory.forTab(tab);
+  const toolbox = await gDevTools.showToolbox(target, "accessibility");
   return toolbox.getCurrentPanel();
 }
 
@@ -140,7 +140,7 @@ async function initAccessibilityPanel(tab = gBrowser.selectedTab) {
  */
 async function checkTreeState(doc, expected) {
   info("Checking tree state.");
-  let hasExpectedStructure = await BrowserTestUtils.waitForCondition(() =>
+  const hasExpectedStructure = await BrowserTestUtils.waitForCondition(() =>
     [...doc.querySelectorAll(".treeRow")].every((row, i) =>
       row.querySelector(".treeLabelCell").textContent === expected[i].role &&
       row.querySelector(".treeValueCell").textContent === expected[i].name),
@@ -158,8 +158,8 @@ async function checkTreeState(doc, expected) {
 async function checkSidebarState(store, expectedState) {
   info("Checking sidebar state.");
   await waitUntilState(store, ({ details }) => {
-    for (let key of ORDERED_PROPS) {
-      let expected = expectedState[key];
+    for (const key of ORDERED_PROPS) {
+      const expected = expectedState[key];
       if (expected === undefined) {
         continue;
       }
@@ -195,9 +195,9 @@ function selectRow(doc, rowNumber) {
  * @param  {Number}   rowNumber number of the row/tree node to be toggled.
  */
 async function toggleRow(doc, rowNumber) {
-  let win = doc.defaultView;
-  let twisty = doc.querySelectorAll(".theme-twisty")[rowNumber];
-  let expected = !twisty.classList.contains("open");
+  const win = doc.defaultView;
+  const twisty = doc.querySelectorAll(".theme-twisty")[rowNumber];
+  const expected = !twisty.classList.contains("open");
 
   info(`${expected ? "Expanding" : "Collapsing"} row ${rowNumber}.`);
 
@@ -223,14 +223,14 @@ async function toggleRow(doc, rowNumber) {
  *                       structure as the return value of 'addTestTab' funciton)
  */
 async function runA11yPanelTests(tests, env) {
-  for (let { desc, action, expected } of tests) {
+  for (const { desc, action, expected } of tests) {
     info(desc);
 
     if (action) {
       await action(env);
     }
 
-    let { tree, sidebar } = expected;
+    const { tree, sidebar } = expected;
     if (tree) {
       await checkTreeState(env.doc, tree);
     }
@@ -278,7 +278,7 @@ function addA11yPanelTestsTask(tests, uri, msg) {
 function addA11YPanelTask(msg, uri, task) {
   add_task(async function a11YPanelTask() {
     info(msg);
-    let env = await addTestTab(buildURL(uri));
+    const env = await addTestTab(buildURL(uri));
     await task(env);
     await disableAccessibilityInspector(env);
   });

devtools/client/application/initializer.js

@@ -66,12 +66,12 @@ window.Application = {
    */
   async createMessageContexts() {
     const locales = Services.locale.getAppLocalesAsBCP47();
-    let generator = L10nRegistry.generateContexts(locales, ["devtools/application.ftl"]);
+    const generator = L10nRegistry.generateContexts(locales, ["devtools/application.ftl"]);
 
     // Return value of generateContexts is a generator and should be converted to
     // a sync iterable before using it with React.
-    let contexts = [];
-    for await (let message of generator) {
+    const contexts = [];
+    for await (const message of generator) {
       contexts.push(message);
     }
 
@@ -79,7 +79,7 @@ window.Application = {
   },
 
   async updateWorkers() {
-    let { service } = await this.client.mainRoot.listAllWorkers();
+    const { service } = await this.client.mainRoot.listAllWorkers();
     this.actions.updateWorkers(service);
   },
 

devtools/client/application/src/components/Worker.js

@@ -54,7 +54,7 @@ class Worker extends Component {
       return;
     }
 
-    let { client, worker } = this.props;
+    const { client, worker } = this.props;
     gDevToolsBrowser.openWorkerToolbox(client, worker.workerActor);
   }
 
@@ -64,7 +64,7 @@ class Worker extends Component {
       return;
     }
 
-    let { client, worker } = this.props;
+    const { client, worker } = this.props;
     client.request({
       to: worker.registrationActor,
       type: "start"
@@ -72,7 +72,7 @@ class Worker extends Component {
   }
 
   unregister() {
-    let { client, worker } = this.props;
+    const { client, worker } = this.props;
     client.request({
       to: worker.registrationActor,
       type: "unregister"
@@ -101,18 +101,18 @@ class Worker extends Component {
   }
 
   formatScope(scope) {
-    let [, remainder] = getUnicodeUrl(scope).split("://");
+    const [, remainder] = getUnicodeUrl(scope).split("://");
     return remainder || scope;
   }
 
   formatSource(source) {
-    let parts = source.split("/");
+    const parts = source.split("/");
     return getUnicodeUrlPath(parts[parts.length - 1]);
   }
 
   render() {
-    let { worker } = this.props;
-    let status = this.getServiceWorkerStatus();
+    const { worker } = this.props;
+    const status = this.getServiceWorkerStatus();
 
     const unregisterButton = this.isActive() ?
       Localized(

devtools/client/application/src/reducers/page-state.js

@@ -22,7 +22,7 @@ function getDomainFromUrl(url) {
 function pageReducer(state = PageState(), action) {
   switch (action.type) {
     case UPDATE_DOMAIN: {
-      let { url } = action;
+      const { url } = action;
       return {
         domain: getDomainFromUrl(url)
       };

devtools/client/application/src/reducers/workers-state.js

@@ -18,7 +18,7 @@ function WorkersState() {
 function workersReducer(state = WorkersState(), action) {
   switch (action.type) {
     case UPDATE_WORKERS: {
-      let { workers } = action;
+      const { workers } = action;
       return { list: workers };
     }
 

devtools/client/application/test/browser_application_panel_debug-service-worker.js

@@ -13,26 +13,26 @@ const TAB_URL = URL_ROOT + "service-workers/debug.html";
 add_task(async function() {
   await enableApplicationPanel();
 
-  let { panel, tab, target } = await openNewTabAndApplicationPanel(TAB_URL);
-  let doc = panel.panelWin.document;
+  const { panel, tab, target } = await openNewTabAndApplicationPanel(TAB_URL);
+  const doc = panel.panelWin.document;
 
   info("Wait until the service worker appears in the application panel");
   await waitUntil(() => getWorkerContainers(doc).length === 1);
 
-  let container = getWorkerContainers(doc)[0];
+  const container = getWorkerContainers(doc)[0];
   info("Wait until the debug link is displayed and enabled");
   await waitUntil(() =>
     container.querySelector(".js-debug-link:not(.worker__debug-link--disabled)"));
 
   info("Click on the debug link and wait for the new toolbox to be ready");
-  let onToolboxReady = gDevTools.once("toolbox-ready");
+  const onToolboxReady = gDevTools.once("toolbox-ready");
 
-  let debugLink = container.querySelector(".js-debug-link");
+  const debugLink = container.querySelector(".js-debug-link");
   debugLink.click();
 
-  let serviceWorkerToolbox = await onToolboxReady;
+  const serviceWorkerToolbox = await onToolboxReady;
   await serviceWorkerToolbox.selectTool("jsdebugger");
-  let debuggerContext = createDebuggerContext(serviceWorkerToolbox);
+  const debuggerContext = createDebuggerContext(serviceWorkerToolbox);
 
   await waitForSources(debuggerContext, "debug-sw.js");
   await selectSource(debuggerContext, "debug-sw.js");

devtools/client/application/test/browser_application_panel_list-domain-workers.js

@@ -16,8 +16,8 @@ const EMPTY_URL = (URL_ROOT + "service-workers/empty.html")
 add_task(async function() {
   await enableApplicationPanel();
 
-  let { panel, target } = await openNewTabAndApplicationPanel(SIMPLE_URL);
-  let doc = panel.panelWin.document;
+  const { panel, target } = await openNewTabAndApplicationPanel(SIMPLE_URL);
+  const doc = panel.panelWin.document;
 
   info("Wait until the service worker appears in the application panel");
   await waitUntil(() => getWorkerContainers(doc).length === 1);

devtools/client/application/test/browser_application_panel_list-several-workers.js

@@ -14,8 +14,8 @@ const OTHER_SCOPE_URL = URL_ROOT + "service-workers/scope-page.html";
 add_task(async function() {
   await enableApplicationPanel();
 
-  let { panel, target } = await openNewTabAndApplicationPanel(SIMPLE_URL);
-  let doc = panel.panelWin.document;
+  const { panel, target } = await openNewTabAndApplicationPanel(SIMPLE_URL);
+  const doc = panel.panelWin.document;
 
   info("Wait until the service worker appears in the application panel");
   await waitUntil(() => getWorkerContainers(doc).length === 1);

devtools/client/application/test/browser_application_panel_list-single-worker.js

@@ -8,10 +8,10 @@ const TAB_URL = URL_ROOT + "service-workers/dynamic-registration.html";
 add_task(async function() {
   await enableApplicationPanel();
 
-  let { panel, tab } = await openNewTabAndApplicationPanel(TAB_URL);
-  let doc = panel.panelWin.document;
+  const { panel, tab } = await openNewTabAndApplicationPanel(TAB_URL);
+  const doc = panel.panelWin.document;
 
-  let isWorkerListEmpty = !!doc.querySelector(".worker-list-empty");
+  const isWorkerListEmpty = !!doc.querySelector(".worker-list-empty");
   ok(isWorkerListEmpty, "No Service Worker displayed");
 
   info("Register a service worker in the page.");
@@ -22,24 +22,24 @@ add_task(async function() {
   info("Wait until the service worker appears in the application panel");
   await waitUntil(() => getWorkerContainers(doc).length > 0);
 
-  let workerContainer = getWorkerContainers(doc)[0];
+  const workerContainer = getWorkerContainers(doc)[0];
 
   info("Wait until the unregister button is displayed for the service worker");
   await waitUntil(() => workerContainer.querySelector(".js-unregister-button"));
 
-  let scopeEl = workerContainer.querySelector(".js-sw-scope");
-  let expectedScope = "example.com/browser/devtools/client/application/test/" +
+  const scopeEl = workerContainer.querySelector(".js-sw-scope");
+  const expectedScope = "example.com/browser/devtools/client/application/test/" +
                       "service-workers/";
   ok(scopeEl.textContent.startsWith(expectedScope),
     "Service worker has the expected scope");
 
-  let updatedEl = workerContainer.querySelector(".js-sw-updated");
+  const updatedEl = workerContainer.querySelector(".js-sw-updated");
   ok(updatedEl.textContent.includes(`${new Date().getFullYear()}`),
     "Service worker has a last updated time");
 
   info("Unregister the service worker");
   await ContentTask.spawn(tab.linkedBrowser, {}, async function() {
-    let registration = await content.wrappedJSObject.sw;
+    const registration = await content.wrappedJSObject.sw;
     registration.unregister();
   });
 

devtools/client/application/test/browser_application_panel_list-unicode.js

@@ -14,22 +14,22 @@ const TAB_URL = (URL_ROOT + "service-workers/simple-unicode.html")
 add_task(async function() {
   await enableApplicationPanel();
 
-  let { panel, target } = await openNewTabAndApplicationPanel(TAB_URL);
-  let doc = panel.panelWin.document;
+  const { panel, target } = await openNewTabAndApplicationPanel(TAB_URL);
+  const doc = panel.panelWin.document;
 
   info("Wait until the service worker appears in the application panel");
   await waitUntil(() => getWorkerContainers(doc).length === 1);
 
-  let workerContainer = getWorkerContainers(doc)[0];
+  const workerContainer = getWorkerContainers(doc)[0];
 
-  let scopeEl = workerContainer.querySelector(".js-sw-scope");
+  const scopeEl = workerContainer.querySelector(".js-sw-scope");
   ok(
     scopeEl.textContent.startsWith(
       "\u03C0\u03B1\u03C1\u03AC\u03B4\u03B5\u03B9\u03B3\u03BC\u03B1." +
       "\u03B4\u03BF\u03BA\u03B9\u03BC\u03AE"),
     "Service worker has the expected Unicode scope"
   );
-  let urlEl = workerContainer.querySelector(".js-source-url");
+  const urlEl = workerContainer.querySelector(".js-source-url");
   ok(
     urlEl.textContent.endsWith("\u65E5\u672C"),
     "Service worker has the expected Unicode url"

devtools/client/application/test/head.js

@@ -46,12 +46,12 @@ function navigate(target, url, waitForTargetEvent = "navigate") {
 }
 
 async function openNewTabAndApplicationPanel(url) {
-  let tab = await addTab(url);
-  let target = TargetFactory.forTab(tab);
+  const tab = await addTab(url);
+  const target = TargetFactory.forTab(tab);
   await target.makeRemote();
 
-  let toolbox = await gDevTools.showToolbox(target, "application");
-  let panel = toolbox.getCurrentPanel();
+  const toolbox = await gDevTools.showToolbox(target, "application");
+  const panel = toolbox.getCurrentPanel();
   return { panel, tab, target, toolbox };
 }
 
@@ -66,7 +66,7 @@ async function unregisterAllWorkers(client) {
   });
 
   info("Unregister all service workers");
-  for (let worker of workers.service) {
+  for (const worker of workers.service) {
     await client.request({
       to: worker.registrationActor,
       type: "unregister"

devtools/client/application/test/service-workers/debug-sw.js

@@ -5,6 +5,6 @@
 
 // Bug 1328293
 self.onfetch = function(event) {
-  let a = 5;
+  const a = 5;
   console.log(a);
 };

devtools/client/canvasdebugger/callslist.js

@@ -49,46 +49,46 @@ var CallsListView = extend(WidgetMethods, {
     this.empty();
 
     for (let i = 0, len = functionCalls.length; i < len; i++) {
-      let call = functionCalls[i];
+      const call = functionCalls[i];
 
-      let view = document.createElement("vbox");
+      const view = document.createElement("vbox");
       view.className = "call-item-view devtools-monospace";
       view.setAttribute("flex", "1");
 
-      let contents = document.createElement("hbox");
+      const contents = document.createElement("hbox");
       contents.className = "call-item-contents";
       contents.setAttribute("align", "center");
       contents.addEventListener("dblclick", this._onExpand);
       view.appendChild(contents);
 
-      let index = document.createElement("label");
+      const index = document.createElement("label");
       index.className = "plain call-item-index";
       index.setAttribute("flex", "1");
       index.setAttribute("value", i + 1);
 
-      let gutter = document.createElement("hbox");
+      const gutter = document.createElement("hbox");
       gutter.className = "call-item-gutter";
       gutter.appendChild(index);
       contents.appendChild(gutter);
 
       if (call.callerPreview) {
-        let context = document.createElement("label");
+        const context = document.createElement("label");
         context.className = "plain call-item-context";
         context.setAttribute("value", call.callerPreview);
         contents.appendChild(context);
 
-        let separator = document.createElement("label");
+        const separator = document.createElement("label");
         separator.className = "plain call-item-separator";
         separator.setAttribute("value", ".");
         contents.appendChild(separator);
       }
 
-      let name = document.createElement("label");
+      const name = document.createElement("label");
       name.className = "plain call-item-name";
       name.setAttribute("value", call.name);
       contents.appendChild(name);
 
-      let argsPreview = document.createElement("label");
+      const argsPreview = document.createElement("label");
       argsPreview.className = "plain call-item-args";
       argsPreview.setAttribute("crop", "end");
       argsPreview.setAttribute("flex", "100");
@@ -100,7 +100,7 @@ var CallsListView = extend(WidgetMethods, {
       }
       contents.appendChild(argsPreview);
 
-      let location = document.createElement("label");
+      const location = document.createElement("label");
       location.className = "plain call-item-location";
       location.setAttribute("value", getFileName(call.file) + ":" + call.line);
       location.setAttribute("crop", "start");
@@ -139,15 +139,15 @@ var CallsListView = extend(WidgetMethods, {
    *        A single "snapshot-image" instance received from the backend.
    */
   showScreenshot: function(screenshot) {
-    let { index, width, height, scaling, flipped, pixels } = screenshot;
+    const { index, width, height, scaling, flipped, pixels } = screenshot;
 
-    let screenshotNode = $("#screenshot-image");
+    const screenshotNode = $("#screenshot-image");
     screenshotNode.setAttribute("flipped", flipped);
     drawBackground("screenshot-rendering", width, height, pixels);
 
-    let dimensionsNode = $("#screenshot-dimensions");
-    let actualWidth = (width / scaling) | 0;
-    let actualHeight = (height / scaling) | 0;
+    const dimensionsNode = $("#screenshot-dimensions");
+    const actualWidth = (width / scaling) | 0;
+    const actualHeight = (height / scaling) | 0;
     dimensionsNode.setAttribute("value",
       SHARED_L10N.getFormatStr("dimensions", actualWidth, actualHeight));
 
@@ -165,7 +165,7 @@ var CallsListView = extend(WidgetMethods, {
     while (this._filmstrip.hasChildNodes()) {
       this._filmstrip.firstChild.remove();
     }
-    for (let thumbnail of thumbnails) {
+    for (const thumbnail of thumbnails) {
       this.appendThumbnail(thumbnail);
     }
 
@@ -180,9 +180,9 @@ var CallsListView = extend(WidgetMethods, {
    *        A single "snapshot-image" instance received from the backend.
    */
   appendThumbnail: function(thumbnail) {
-    let { index, width, height, flipped, pixels } = thumbnail;
+    const { index, width, height, flipped, pixels } = thumbnail;
 
-    let thumbnailNode = document.createElementNS(HTML_NS, "canvas");
+    const thumbnailNode = document.createElementNS(HTML_NS, "canvas");
     thumbnailNode.setAttribute("flipped", flipped);
     thumbnailNode.width = Math.max(CanvasFront.THUMBNAIL_SIZE, width);
     thumbnailNode.height = Math.max(CanvasFront.THUMBNAIL_SIZE, height);
@@ -203,13 +203,13 @@ var CallsListView = extend(WidgetMethods, {
    *        The context function call's index.
    */
   set highlightedThumbnail(index) {
-    let currHighlightedThumbnail = $(".filmstrip-thumbnail[index='" + index + "']");
+    const currHighlightedThumbnail = $(".filmstrip-thumbnail[index='" + index + "']");
     if (currHighlightedThumbnail == null) {
       return;
     }
 
-    let prevIndex = this._highlightedThumbnailIndex;
-    let prevHighlightedThumbnail = $(".filmstrip-thumbnail[index='" + prevIndex + "']");
+    const prevIndex = this._highlightedThumbnailIndex;
+    const prevHighlightedThumbnail = $(".filmstrip-thumbnail[index='" + prevIndex + "']");
     if (prevHighlightedThumbnail) {
       prevHighlightedThumbnail.removeAttribute("highlighted");
     }
@@ -259,8 +259,8 @@ var CallsListView = extend(WidgetMethods, {
     setConditionalTimeout("screenshot-display", SCREENSHOT_DISPLAY_DELAY, () => {
       return !this._isSliding;
     }, () => {
-      let frameSnapshot = SnapshotsListView.selectedItem.attachment.actor;
-      let functionCall = callItem.attachment.actor;
+      const frameSnapshot = SnapshotsListView.selectedItem.attachment.actor;
+      const functionCall = callItem.attachment.actor;
       frameSnapshot.generateScreenshotFor(functionCall).then(screenshot => {
         this.showScreenshot(screenshot);
         this.highlightedThumbnail = screenshot.index;
@@ -272,14 +272,14 @@ var CallsListView = extend(WidgetMethods, {
    * The input listener for the calls searchbox.
    */
   _onSearch: function(e) {
-    let lowerCaseSearchToken = this._searchbox.value.toLowerCase();
+    const lowerCaseSearchToken = this._searchbox.value.toLowerCase();
 
     this.filterContents(e => {
-      let call = e.attachment.actor;
-      let name = call.name.toLowerCase();
-      let file = call.file.toLowerCase();
-      let line = call.line.toString().toLowerCase();
-      let args = call.argsPreview.toLowerCase();
+      const call = e.attachment.actor;
+      const name = call.name.toLowerCase();
+      const file = call.file.toLowerCase();
+      const line = call.line.toString().toLowerCase();
+      const args = call.argsPreview.toLowerCase();
 
       return name.includes(lowerCaseSearchToken) ||
              file.includes(lowerCaseSearchToken) ||
@@ -300,18 +300,18 @@ var CallsListView = extend(WidgetMethods, {
    * When expanding an item, it's corresponding call stack will be displayed.
    */
   _onExpand: function(e) {
-    let callItem = this.getItemForElement(e.target);
-    let view = $(".call-item-view", callItem.target);
+    const callItem = this.getItemForElement(e.target);
+    const view = $(".call-item-view", callItem.target);
 
     // If the call stack nodes were already created, simply re-show them
     // or jump to the corresponding file and line in the Debugger if a
     // location link was clicked.
     if (view.hasAttribute("call-stack-populated")) {
-      let isExpanded = view.getAttribute("call-stack-expanded") == "true";
+      const isExpanded = view.getAttribute("call-stack-expanded") == "true";
 
       // If clicking on the location, jump to the Debugger.
       if (e.target.classList.contains("call-item-location")) {
-        let { file, line } = callItem.attachment.actor;
+        const { file, line } = callItem.attachment.actor;
         this._viewSourceInDebugger(file, line);
         return;
       }
@@ -322,7 +322,7 @@ var CallsListView = extend(WidgetMethods, {
       return;
     }
 
-    let list = document.createElement("vbox");
+    const list = document.createElement("vbox");
     list.className = "call-item-stack";
     view.setAttribute("call-stack-populated", "");
     view.setAttribute("call-stack-expanded", "true");
@@ -331,24 +331,24 @@ var CallsListView = extend(WidgetMethods, {
     /**
      * Creates a function call nodes in this container for a stack.
      */
-    let display = stack => {
+    const display = stack => {
       for (let i = 1; i < stack.length; i++) {
-        let call = stack[i];
+        const call = stack[i];
 
-        let contents = document.createElement("hbox");
+        const contents = document.createElement("hbox");
         contents.className = "call-item-stack-fn";
         contents.style.paddingInlineStart = (i * STACK_FUNC_INDENTATION) + "px";
 
-        let name = document.createElement("label");
+        const name = document.createElement("label");
         name.className = "plain call-item-stack-fn-name";
         name.setAttribute("value", "↳ " + call.name + "()");
         contents.appendChild(name);
 
-        let spacer = document.createElement("spacer");
+        const spacer = document.createElement("spacer");
         spacer.setAttribute("flex", "100");
         contents.appendChild(spacer);
 
-        let location = document.createElement("label");
+        const location = document.createElement("label");
         location.className = "plain call-item-stack-fn-location";
         location.setAttribute("value", getFileName(call.file) + ":" + call.line);
         location.setAttribute("crop", "start");
@@ -364,7 +364,7 @@ var CallsListView = extend(WidgetMethods, {
 
     // If this animation snapshot is loaded from disk, there are no corresponding
     // backend actors available and the data is immediately available.
-    let functionCall = callItem.attachment.actor;
+    const functionCall = callItem.attachment.actor;
     if (functionCall.isLoadedFromDisk) {
       display(functionCall.stack);
     } else {
@@ -400,7 +400,7 @@ var CallsListView = extend(WidgetMethods, {
    */
   _onResume: function() {
     // Jump to the next draw call in the recorded animation frame snapshot.
-    let drawCall = getNextDrawCall(this.items, this.selectedItem);
+    const drawCall = getNextDrawCall(this.items, this.selectedItem);
     if (drawCall) {
       this.selectedItem = drawCall;
       return;
@@ -425,8 +425,8 @@ var CallsListView = extend(WidgetMethods, {
       this._onResume();
       return;
     }
-    let callItem = this.selectedItem;
-    let { file, line } = callItem.attachment.actor;
+    const callItem = this.selectedItem;
+    const { file, line } = callItem.attachment.actor;
     this._viewSourceInDebugger(file, line);
   },
 

devtools/client/canvasdebugger/canvasdebugger.js

@@ -190,7 +190,7 @@ var $all = (selector, target = document) => target.querySelectorAll(selector);
  */
 function getFileName(url) {
   try {
-    let { fileName } = NetworkHelper.nsIURL(url);
+    const { fileName } = NetworkHelper.nsIURL(url);
     return fileName || "/";
   } catch (e) {
     // This doesn't look like a url, or nsIURL can't handle it.
@@ -213,7 +213,7 @@ function getFileName(url) {
  *         The requested image data buffer.
  */
 function getImageDataStorage(ctx, w, h) {
-  let storage = getImageDataStorage.cache;
+  const storage = getImageDataStorage.cache;
   if (storage && storage.width == w && storage.height == h) {
     return storage;
   }
@@ -244,7 +244,7 @@ getImageDataStorage.cache = null;
  *                      supplied pixels don't completely cover the canvas.
  */
 function drawImage(canvas, width, height, pixels, options = {}) {
-  let ctx = canvas.getContext("2d");
+  const ctx = canvas.getContext("2d");
 
   // FrameSnapshot actors return "snapshot-image" type instances with just an
   // empty pixel array if the source image is completely transparent.
@@ -253,12 +253,12 @@ function drawImage(canvas, width, height, pixels, options = {}) {
     return;
   }
 
-  let imageData = getImageDataStorage(ctx, width, height);
+  const imageData = getImageDataStorage(ctx, width, height);
   imageData.data.set(pixels);
 
   if (options.centered) {
-    let left = (canvas.width - width) / 2;
-    let top = (canvas.height - height) / 2;
+    const left = (canvas.width - width) / 2;
+    const top = (canvas.height - height) / 2;
     ctx.putImageData(imageData, left, top);
   } else {
     ctx.putImageData(imageData, 0, 0);
@@ -279,7 +279,7 @@ function drawImage(canvas, width, height, pixels, options = {}) {
  *        An array buffer view of the image data.
  */
 function drawBackground(id, width, height, pixels) {
-  let canvas = document.createElementNS(HTML_NS, "canvas");
+  const canvas = document.createElementNS(HTML_NS, "canvas");
   canvas.width = width;
   canvas.height = height;
 
@@ -297,8 +297,8 @@ function drawBackground(id, width, height, pixels) {
  */
 function getNextDrawCall(calls, call) {
   for (let i = calls.indexOf(call) + 1, len = calls.length; i < len; i++) {
-    let nextCall = calls[i];
-    let name = nextCall.attachment.actor.name;
+    const nextCall = calls[i];
+    const name = nextCall.attachment.actor.name;
     if (CanvasFront.DRAW_CALLS.has(name)) {
       return nextCall;
     }
@@ -312,8 +312,8 @@ function getNextDrawCall(calls, call) {
  */
 function getScreenshotFromCallLoadedFromDisk(calls, call) {
   for (let i = calls.indexOf(call); i >= 0; i--) {
-    let prevCall = calls[i];
-    let screenshot = prevCall.screenshot;
+    const prevCall = calls[i];
+    const screenshot = prevCall.screenshot;
     if (screenshot) {
       return screenshot;
     }
@@ -326,7 +326,7 @@ function getScreenshotFromCallLoadedFromDisk(calls, call) {
  */
 function getThumbnailForCall(thumbnails, index) {
   for (let i = thumbnails.length - 1; i >= 0; i--) {
-    let thumbnail = thumbnails[i];
+    const thumbnail = thumbnails[i];
     if (thumbnail.index <= index) {
       return thumbnail;
     }

devtools/client/canvasdebugger/snapshotslist.js

@@ -47,36 +47,36 @@ var SnapshotsListView = extend(WidgetMethods, {
    *         The newly inserted item.
    */
   addSnapshot: function() {
-    let contents = document.createElement("hbox");
+    const contents = document.createElement("hbox");
     contents.className = "snapshot-item";
 
-    let thumbnail = document.createElementNS(HTML_NS, "canvas");
+    const thumbnail = document.createElementNS(HTML_NS, "canvas");
     thumbnail.className = "snapshot-item-thumbnail";
     thumbnail.width = CanvasFront.THUMBNAIL_SIZE;
     thumbnail.height = CanvasFront.THUMBNAIL_SIZE;
 
-    let title = document.createElement("label");
+    const title = document.createElement("label");
     title.className = "plain snapshot-item-title";
     title.setAttribute("value",
       L10N.getFormatStr("snapshotsList.itemLabel", this.itemCount + 1));
 
-    let calls = document.createElement("label");
+    const calls = document.createElement("label");
     calls.className = "plain snapshot-item-calls";
     calls.setAttribute("value",
       L10N.getStr("snapshotsList.loadingLabel"));
 
-    let save = document.createElement("label");
+    const save = document.createElement("label");
     save.className = "plain snapshot-item-save";
     save.addEventListener("click", this._onSaveButtonClick);
 
-    let spacer = document.createElement("spacer");
+    const spacer = document.createElement("spacer");
     spacer.setAttribute("flex", "1");
 
-    let footer = document.createElement("hbox");
+    const footer = document.createElement("hbox");
     footer.className = "snapshot-item-footer";
     footer.appendChild(save);
 
-    let details = document.createElement("vbox");
+    const details = document.createElement("vbox");
     details.className = "snapshot-item-details";
     details.appendChild(title);
     details.appendChild(calls);
@@ -125,30 +125,30 @@ var SnapshotsListView = extend(WidgetMethods, {
     // Make sure the function call actors are stored on the item,
     // to be used when populating the CallsListView.
     snapshotItem.attachment.actor = snapshotActor;
-    let functionCalls = snapshotItem.attachment.calls = snapshotOverview.calls;
-    let thumbnails = snapshotItem.attachment.thumbnails = snapshotOverview.thumbnails;
-    let screenshot = snapshotItem.attachment.screenshot = snapshotOverview.screenshot;
+    const functionCalls = snapshotItem.attachment.calls = snapshotOverview.calls;
+    const thumbnails = snapshotItem.attachment.thumbnails = snapshotOverview.thumbnails;
+    const screenshot = snapshotItem.attachment.screenshot = snapshotOverview.screenshot;
 
-    let lastThumbnail = thumbnails[thumbnails.length - 1];
-    let { width, height, flipped, pixels } = lastThumbnail;
+    const lastThumbnail = thumbnails[thumbnails.length - 1];
+    const { width, height, flipped, pixels } = lastThumbnail;
 
-    let thumbnailNode = $(".snapshot-item-thumbnail", snapshotItem.target);
+    const thumbnailNode = $(".snapshot-item-thumbnail", snapshotItem.target);
     thumbnailNode.setAttribute("flipped", flipped);
     drawImage(thumbnailNode, width, height, pixels, { centered: true });
 
-    let callsNode = $(".snapshot-item-calls", snapshotItem.target);
-    let drawCalls = functionCalls.filter(e => CanvasFront.DRAW_CALLS.has(e.name));
+    const callsNode = $(".snapshot-item-calls", snapshotItem.target);
+    const drawCalls = functionCalls.filter(e => CanvasFront.DRAW_CALLS.has(e.name));
 
-    let drawCallsStr = PluralForm.get(drawCalls.length,
+    const drawCallsStr = PluralForm.get(drawCalls.length,
       L10N.getStr("snapshotsList.drawCallsLabel"));
-    let funcCallsStr = PluralForm.get(functionCalls.length,
+    const funcCallsStr = PluralForm.get(functionCalls.length,
       L10N.getStr("snapshotsList.functionCallsLabel"));
 
     callsNode.setAttribute("value",
       drawCallsStr.replace("#1", drawCalls.length) + ", " +
       funcCallsStr.replace("#1", functionCalls.length));
 
-    let saveNode = $(".snapshot-item-save", snapshotItem.target);
+    const saveNode = $(".snapshot-item-save", snapshotItem.target);
     saveNode.setAttribute("disabled", !!snapshotItem.isLoadedFromDisk);
     saveNode.setAttribute("value", snapshotItem.isLoadedFromDisk
       ? L10N.getStr("snapshotsList.loadedLabel")
@@ -169,7 +169,7 @@ var SnapshotsListView = extend(WidgetMethods, {
     if (!snapshotItem || !snapshotItem.attachment.actor) {
       return;
     }
-    let { calls, thumbnails, screenshot } = snapshotItem.attachment;
+    const { calls, thumbnails, screenshot } = snapshotItem.attachment;
 
     $("#reload-notice").hidden = true;
     $("#empty-notice").hidden = true;
@@ -302,7 +302,7 @@ var SnapshotsListView = extend(WidgetMethods, {
    */
   async _stopRecordingAnimation() {
     clearNamedTimeout("canvas-actor-recording");
-    let actorCanStop = await gTarget.actorHasMethod("canvas", "stopRecordingAnimationFrame");
+    const actorCanStop = await gTarget.actorHasMethod("canvas", "stopRecordingAnimationFrame");
 
     if (actorCanStop) {
       await gFront.stopRecordingAnimationFrame();
@@ -325,8 +325,8 @@ var SnapshotsListView = extend(WidgetMethods, {
   async _onRecordSuccess(snapshotActor) {
     // Clear bail-out case if frame found in CANVAS_ACTOR_RECORDING_ATTEMPT milliseconds
     clearNamedTimeout("canvas-actor-recording");
-    let snapshotItem = this.getItemAtIndex(this.itemCount - 1);
-    let snapshotOverview = await snapshotActor.getOverview();
+    const snapshotItem = this.getItemAtIndex(this.itemCount - 1);
+    const snapshotOverview = await snapshotActor.getOverview();
     this.customizeSnapshot(snapshotItem, snapshotActor, snapshotOverview);
 
     this._recording = false;
@@ -351,7 +351,7 @@ var SnapshotsListView = extend(WidgetMethods, {
    * The click listener for the "import" button in this container.
    */
   _onImportButtonClick: function() {
-    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+    const fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
     fp.init(window, L10N.getStr("snapshotsList.saveDialogTitle"), Ci.nsIFilePicker.modeOpen);
     fp.appendFilter(L10N.getStr("snapshotsList.saveDialogJSONFilter"), "*.json");
     fp.appendFilter(L10N.getStr("snapshotsList.saveDialogAllFilter"), "*.*");
@@ -361,7 +361,7 @@ var SnapshotsListView = extend(WidgetMethods, {
         return;
       }
 
-      let channel = NetUtil.newChannel({
+      const channel = NetUtil.newChannel({
         uri: NetUtil.newURI(fp.file), loadUsingSystemPrincipal: true});
       channel.contentType = "text/plain";
 
@@ -372,7 +372,7 @@ var SnapshotsListView = extend(WidgetMethods, {
         }
         var data;
         try {
-          let string = NetUtil.readInputStreamToString(inputStream, inputStream.available());
+          const string = NetUtil.readInputStreamToString(inputStream, inputStream.available());
           data = JSON.parse(string);
         } catch (e) {
           console.error("Could not read animation frame snapshot file.");
@@ -385,7 +385,7 @@ var SnapshotsListView = extend(WidgetMethods, {
 
         // Add a `isLoadedFromDisk` flag on everything to avoid sending invalid
         // requests to the backend, since we're not dealing with actors anymore.
-        let snapshotItem = this.addSnapshot();
+        const snapshotItem = this.addSnapshot();
         snapshotItem.isLoadedFromDisk = true;
         data.calls.forEach(e => e.isLoadedFromDisk = true);
 
@@ -398,9 +398,9 @@ var SnapshotsListView = extend(WidgetMethods, {
    * The click listener for the "save" button of each item in this container.
    */
   _onSaveButtonClick: function(e) {
-    let snapshotItem = this.getItemForElement(e.target);
+    const snapshotItem = this.getItemForElement(e.target);
 
-    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+    const fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
     fp.init(window, L10N.getStr("snapshotsList.saveDialogTitle"), Ci.nsIFilePicker.modeSave);
     fp.appendFilter(L10N.getStr("snapshotsList.saveDialogJSONFilter"), "*.json");
     fp.appendFilter(L10N.getStr("snapshotsList.saveDialogAllFilter"), "*.*");
@@ -408,21 +408,21 @@ var SnapshotsListView = extend(WidgetMethods, {
 
     // Start serializing all the function call actors for the specified snapshot,
     // while the nsIFilePicker dialog is being opened. Snappy.
-    let serialized = (async function() {
-      let data = {
+    const serialized = (async function() {
+      const data = {
         fileType: CALLS_LIST_SERIALIZER_IDENTIFIER,
         version: CALLS_LIST_SERIALIZER_VERSION,
         calls: [],
         thumbnails: [],
         screenshot: null
       };
-      let functionCalls = snapshotItem.attachment.calls;
-      let thumbnails = snapshotItem.attachment.thumbnails;
-      let screenshot = snapshotItem.attachment.screenshot;
+      const functionCalls = snapshotItem.attachment.calls;
+      const thumbnails = snapshotItem.attachment.thumbnails;
+      const screenshot = snapshotItem.attachment.screenshot;
 
       // Prepare all the function calls for serialization.
       await DevToolsUtils.yieldingEach(functionCalls, (call, i) => {
-        let { type, name, file, line, timestamp, argsPreview, callerPreview } = call;
+        const { type, name, file, line, timestamp, argsPreview, callerPreview } = call;
         return call.getDetails().then(({ stack }) => {
           data.calls[i] = {
             type: type,
@@ -439,16 +439,16 @@ var SnapshotsListView = extend(WidgetMethods, {
 
       // Prepare all the thumbnails for serialization.
       await DevToolsUtils.yieldingEach(thumbnails, (thumbnail, i) => {
-        let { index, width, height, flipped, pixels } = thumbnail;
+        const { index, width, height, flipped, pixels } = thumbnail;
         data.thumbnails.push({ index, width, height, flipped, pixels });
       });
 
       // Prepare the screenshot for serialization.
-      let { index, width, height, flipped, pixels } = screenshot;
+      const { index, width, height, flipped, pixels } = screenshot;
       data.screenshot = { index, width, height, flipped, pixels };
 
-      let string = JSON.stringify(data);
-      let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
+      const string = JSON.stringify(data);
+      const converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
         .createInstance(Ci.nsIScriptableUnicodeConverter);
 
       converter.charset = "UTF-8";
@@ -461,8 +461,8 @@ var SnapshotsListView = extend(WidgetMethods, {
       if (result == Ci.nsIFilePicker.returnCancel) {
         return;
       }
-      let footer = $(".snapshot-item-footer", snapshotItem.target);
-      let save = $(".snapshot-item-save", snapshotItem.target);
+      const footer = $(".snapshot-item-footer", snapshotItem.target);
+      const save = $(".snapshot-item-save", snapshotItem.target);
 
       // Show a throbber and a "Saving…" label if serializing isn't immediate.
       setNamedTimeout("call-list-save", CALLS_LIST_SLOW_SAVE_DELAY, () => {
@@ -472,7 +472,7 @@ var SnapshotsListView = extend(WidgetMethods, {
       });
 
       serialized.then(inputStream => {
-        let outputStream = FileUtils.openSafeFileOutputStream(fp.file);
+        const outputStream = FileUtils.openSafeFileOutputStream(fp.file);
 
         NetUtil.asyncCopy(inputStream, outputStream, status => {
           if (!Components.isSuccessCode(status)) {
@@ -489,8 +489,8 @@ var SnapshotsListView = extend(WidgetMethods, {
 });
 
 function showNotification(toolbox, name, message) {
-  let notificationBox = toolbox.getNotificationBox();
-  let notification = notificationBox.getNotificationWithValue(name);
+  const notificationBox = toolbox.getNotificationBox();
+  const notification = notificationBox.getNotificationWithValue(name);
   if (!notification) {
     notificationBox.appendNotification(message, name, "", notificationBox.PRIORITY_WARNING_HIGH);
   }

devtools/client/canvasdebugger/test/browser_canvas-actor-test-01.js

@@ -7,7 +7,7 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCallWatcherBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCallWatcherBackend(SIMPLE_CANVAS_URL);
 
   ok(target, "Should have a target available.");
   ok(front, "Should have a protocol front available.");

devtools/client/canvasdebugger/test/browser_canvas-actor-test-02.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCallWatcherBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCallWatcherBackend(SIMPLE_CANVAS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({
     tracedGlobals: ["CanvasRenderingContext2D", "WebGLRenderingContext"],
@@ -25,7 +25,7 @@ async function ifTestingSupported() {
   // Allow the content to execute some functions.
   await waitForTick();
 
-  let functionCalls = await front.pauseRecording();
+  const functionCalls = await front.pauseRecording();
   ok(functionCalls,
     "An array of function call actors was sent after reloading.");
   ok(functionCalls.length > 0,
@@ -45,7 +45,7 @@ async function ifTestingSupported() {
   is(functionCalls[0].argsPreview, "0, 0, 128, 128",
     "The called function's args preview is correct.");
 
-  let details = await functionCalls[1].getDetails();
+  const details = await functionCalls[1].getDetails();
   ok(details,
     "The first called function has some details available.");
 

devtools/client/canvasdebugger/test/browser_canvas-actor-test-03.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,15 +17,15 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
+  const snapshotActor = await front.recordAnimationFrame();
   ok(snapshotActor,
     "A snapshot actor was sent after recording.");
 
-  let animationOverview = await snapshotActor.getOverview();
+  const animationOverview = await snapshotActor.getOverview();
   ok(snapshotActor,
     "An animation overview could be retrieved after recording.");
 
-  let functionCalls = animationOverview.calls;
+  const functionCalls = animationOverview.calls;
   ok(functionCalls,
     "An array of function call actors was sent after recording.");
   is(functionCalls.length, 8,

devtools/client/canvasdebugger/test/browser_canvas-actor-test-04.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,15 +17,15 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
+  const snapshotActor = await front.recordAnimationFrame();
   ok(snapshotActor,
     "A snapshot actor was sent after recording.");
 
-  let animationOverview = await snapshotActor.getOverview();
+  const animationOverview = await snapshotActor.getOverview();
   ok(animationOverview,
     "An animation overview could be retrieved after recording.");
 
-  let thumbnails = animationOverview.thumbnails;
+  const thumbnails = animationOverview.thumbnails;
   ok(thumbnails,
     "An array of thumbnails was sent after recording.");
   is(thumbnails.length, 4,
@@ -80,6 +80,6 @@ async function ifTestingSupported() {
 }
 
 function Uint32(src) {
-  let charView = new Uint8Array(src);
+  const charView = new Uint8Array(src);
   return new Uint32Array(charView.buffer);
 }

devtools/client/canvasdebugger/test/browser_canvas-actor-test-05.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,15 +17,15 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
+  const snapshotActor = await front.recordAnimationFrame();
   ok(snapshotActor,
     "A snapshot actor was sent after recording.");
 
-  let animationOverview = await snapshotActor.getOverview();
+  const animationOverview = await snapshotActor.getOverview();
   ok(snapshotActor,
     "An animation overview could be retrieved after recording.");
 
-  let screenshot = animationOverview.screenshot;
+  const screenshot = animationOverview.screenshot;
   ok(screenshot,
     "A screenshot was sent after recording.");
 
@@ -45,6 +45,6 @@ async function ifTestingSupported() {
 }
 
 function Uint32(src) {
-  let charView = new Uint8Array(src);
+  const charView = new Uint8Array(src);
   return new Uint32Array(charView.buffer);
 }

devtools/client/canvasdebugger/test/browser_canvas-actor-test-06.js

@@ -6,9 +6,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_TRANSPARENT_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_TRANSPARENT_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -16,10 +16,10 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
-  let animationOverview = await snapshotActor.getOverview();
+  const snapshotActor = await front.recordAnimationFrame();
+  const animationOverview = await snapshotActor.getOverview();
 
-  let functionCalls = animationOverview.calls;
+  const functionCalls = animationOverview.calls;
   ok(functionCalls,
     "An array of function call actors was sent after recording.");
   is(functionCalls.length, 8,
@@ -34,10 +34,10 @@ async function ifTestingSupported() {
   is(functionCalls[6].name, "fillRect",
     "The fourth called function's name is correct.");
 
-  let firstDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
-  let secondDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
-  let thirdDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[4]);
-  let fourthDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
+  const firstDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
+  const secondDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
+  const thirdDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[4]);
+  const fourthDrawCallScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
 
   ok(firstDrawCallScreenshot,
     "The first draw call has a screenshot attached.");
@@ -95,6 +95,6 @@ async function ifTestingSupported() {
 }
 
 function Uint32(src) {
-  let charView = new Uint8Array(src);
+  const charView = new Uint8Array(src);
   return new Uint32Array(charView.buffer);
 }

devtools/client/canvasdebugger/test/browser_canvas-actor-test-07.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_CANVAS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,18 +17,18 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
-  let animationOverview = await snapshotActor.getOverview();
+  const snapshotActor = await front.recordAnimationFrame();
+  const animationOverview = await snapshotActor.getOverview();
 
-  let functionCalls = animationOverview.calls;
+  const functionCalls = animationOverview.calls;
   ok(functionCalls,
     "An array of function call actors was sent after recording.");
   is(functionCalls.length, 8,
     "The number of function call actors is correct.");
 
-  let firstNonDrawCall = await functionCalls[1].getDetails();
-  let secondNonDrawCall = await functionCalls[3].getDetails();
-  let lastNonDrawCall = await functionCalls[7].getDetails();
+  const firstNonDrawCall = await functionCalls[1].getDetails();
+  const secondNonDrawCall = await functionCalls[3].getDetails();
+  const lastNonDrawCall = await functionCalls[7].getDetails();
 
   is(firstNonDrawCall.name, "fillStyle",
     "The first non-draw function's name is correct.");
@@ -37,9 +37,9 @@ async function ifTestingSupported() {
   is(lastNonDrawCall.name, "requestAnimationFrame",
     "The last non-draw function's name is correct.");
 
-  let firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
-  let secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[3]);
-  let lastScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[7]);
+  const firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
+  const secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[3]);
+  const lastScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[7]);
 
   ok(firstScreenshot,
     "A screenshot was successfully retrieved for the first non-draw function.");
@@ -48,7 +48,7 @@ async function ifTestingSupported() {
   ok(lastScreenshot,
     "A screenshot was successfully retrieved for the last non-draw function.");
 
-  let firstActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
+  const firstActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
   ok(sameArray(firstScreenshot.pixels, firstActualScreenshot.pixels),
     "The screenshot for the first non-draw function is correct.");
   is(firstScreenshot.width, 128,
@@ -56,7 +56,7 @@ async function ifTestingSupported() {
   is(firstScreenshot.height, 128,
     "The screenshot for the first non-draw function has the correct height.");
 
-  let secondActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
+  const secondActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
   ok(sameArray(secondScreenshot.pixels, secondActualScreenshot.pixels),
     "The screenshot for the second non-draw function is correct.");
   is(secondScreenshot.width, 128,
@@ -64,7 +64,7 @@ async function ifTestingSupported() {
   is(secondScreenshot.height, 128,
     "The screenshot for the second non-draw function has the correct height.");
 
-  let lastActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
+  const lastActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
   ok(sameArray(lastScreenshot.pixels, lastActualScreenshot.pixels),
     "The screenshot for the last non-draw function is correct.");
   is(lastScreenshot.width, 128,

devtools/client/canvasdebugger/test/browser_canvas-actor-test-08.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SIMPLE_BITMASKS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SIMPLE_BITMASKS_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,9 +17,9 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
-  let animationOverview = await snapshotActor.getOverview();
-  let functionCalls = animationOverview.calls;
+  const snapshotActor = await front.recordAnimationFrame();
+  const animationOverview = await snapshotActor.getOverview();
+  const functionCalls = animationOverview.calls;
 
   is(functionCalls[0].name, "clearRect",
     "The first called function's name is correct.");

devtools/client/canvasdebugger/test/browser_canvas-actor-test-09.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(WEBGL_ENUM_URL);
+  const { target, front } = await initCanvasDebuggerBackend(WEBGL_ENUM_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,9 +17,9 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
-  let animationOverview = await snapshotActor.getOverview();
-  let functionCalls = animationOverview.calls;
+  const snapshotActor = await front.recordAnimationFrame();
+  const animationOverview = await snapshotActor.getOverview();
+  const functionCalls = animationOverview.calls;
 
   is(functionCalls[0].name, "clear",
     "The function's name is correct.");

devtools/client/canvasdebugger/test/browser_canvas-actor-test-10.js

@@ -7,10 +7,10 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(WEBGL_BINDINGS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(WEBGL_BINDINGS_URL);
   loadFrameScriptUtils();
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -18,11 +18,11 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
-  let animationOverview = await snapshotActor.getOverview();
-  let functionCalls = animationOverview.calls;
+  const snapshotActor = await front.recordAnimationFrame();
+  const animationOverview = await snapshotActor.getOverview();
+  const functionCalls = animationOverview.calls;
 
-  let firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
+  const firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
   is(firstScreenshot.index, -1,
     "The first screenshot didn't encounter any draw call.");
   is(firstScreenshot.scaling, 0.25,
@@ -58,7 +58,7 @@ async function ifTestingSupported() {
     512,
     "The debuggee's gl context viewport's left coord. wasn't changed.");
 
-  let secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
+  const secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
   is(secondScreenshot.index, 1,
     "The second screenshot has the correct index.");
   is(secondScreenshot.width, CanvasFront.WEBGL_SCREENSHOT_MAX_HEIGHT,

devtools/client/canvasdebugger/test/browser_canvas-actor-test-11.js

@@ -7,9 +7,9 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(SET_TIMEOUT_URL);
+  const { target, front } = await initCanvasDebuggerBackend(SET_TIMEOUT_URL);
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -17,15 +17,15 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let snapshotActor = await front.recordAnimationFrame();
+  const snapshotActor = await front.recordAnimationFrame();
   ok(snapshotActor,
     "A snapshot actor was sent after recording.");
 
-  let animationOverview = await snapshotActor.getOverview();
+  const animationOverview = await snapshotActor.getOverview();
   ok(snapshotActor,
     "An animation overview could be retrieved after recording.");
 
-  let functionCalls = animationOverview.calls;
+  const functionCalls = animationOverview.calls;
   ok(functionCalls,
     "An array of function call actors was sent after recording.");
   is(functionCalls.length, 8,
@@ -70,9 +70,9 @@ async function ifTestingSupported() {
   is(functionCalls[7].callerPreview, "Object",
     "The last called function's caller preview is correct.");
 
-  let firstNonDrawCall = await functionCalls[1].getDetails();
-  let secondNonDrawCall = await functionCalls[3].getDetails();
-  let lastNonDrawCall = await functionCalls[7].getDetails();
+  const firstNonDrawCall = await functionCalls[1].getDetails();
+  const secondNonDrawCall = await functionCalls[3].getDetails();
+  const lastNonDrawCall = await functionCalls[7].getDetails();
 
   is(firstNonDrawCall.name, "fillStyle",
     "The first non-draw function's name is correct.");
@@ -81,9 +81,9 @@ async function ifTestingSupported() {
   is(lastNonDrawCall.name, "setTimeout",
     "The last non-draw function's name is correct.");
 
-  let firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
-  let secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[3]);
-  let lastScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[7]);
+  const firstScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[1]);
+  const secondScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[3]);
+  const lastScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[7]);
 
   ok(firstScreenshot,
     "A screenshot was successfully retrieved for the first non-draw function.");
@@ -92,7 +92,7 @@ async function ifTestingSupported() {
   ok(lastScreenshot,
     "A screenshot was successfully retrieved for the last non-draw function.");
 
-  let firstActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
+  const firstActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[0]);
   ok(sameArray(firstScreenshot.pixels, firstActualScreenshot.pixels),
     "The screenshot for the first non-draw function is correct.");
   is(firstScreenshot.width, 128,
@@ -100,7 +100,7 @@ async function ifTestingSupported() {
   is(firstScreenshot.height, 128,
     "The screenshot for the first non-draw function has the correct height.");
 
-  let secondActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
+  const secondActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[2]);
   ok(sameArray(secondScreenshot.pixels, secondActualScreenshot.pixels),
     "The screenshot for the second non-draw function is correct.");
   is(secondScreenshot.width, 128,
@@ -108,7 +108,7 @@ async function ifTestingSupported() {
   is(secondScreenshot.height, 128,
     "The screenshot for the second non-draw function has the correct height.");
 
-  let lastActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
+  const lastActualScreenshot = await snapshotActor.generateScreenshotFor(functionCalls[6]);
   ok(sameArray(lastScreenshot.pixels, lastActualScreenshot.pixels),
     "The screenshot for the last non-draw function is correct.");
   is(lastScreenshot.width, 128,

devtools/client/canvasdebugger/test/browser_canvas-actor-test-12.js

@@ -7,10 +7,10 @@
  */
 
 async function ifTestingSupported() {
-  let { target, front } = await initCanvasDebuggerBackend(NO_CANVAS_URL);
+  const { target, front } = await initCanvasDebuggerBackend(NO_CANVAS_URL);
   loadFrameScriptUtils();
 
-  let navigated = once(target, "navigate");
+  const navigated = once(target, "navigate");
 
   await front.setup({ reload: true });
   ok(true, "The front was setup up successfully.");
@@ -18,7 +18,7 @@ async function ifTestingSupported() {
   await navigated;
   ok(true, "Target automatically navigated when the front was set up.");
 
-  let startRecording = front.recordAnimationFrame();
+  const startRecording = front.recordAnimationFrame();
   await front.stopRecordingAnimationFrame();
 
   ok(!(await startRecording),

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-highlight.js

@@ -6,13 +6,13 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated]);
 

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-list.js

@@ -7,13 +7,13 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated]);
 
@@ -42,7 +42,7 @@ async function ifTestingSupported() {
     "8", "", "requestAnimationFrame", "(Function)", "doc_simple-canvas.html:30");
 
   function testItem(item, index, context, name, args, location) {
-    let i = CallsListView.indexOfItem(item);
+    const i = CallsListView.indexOfItem(item);
     is(i, index - 1,
       "The item at index " + index + " is correctly displayed in the UI.");
 

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-search.js

@@ -6,13 +6,13 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
-  let searchbox = $("#calls-searchbox");
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const searchbox = $("#calls-searchbox");
 
   await reload(target);
 
-  let firstRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const firstRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([firstRecordingFinished, callListPopulated]);
@@ -43,7 +43,7 @@ async function ifTestingSupported() {
   is(CallsListView.visibleItems[0].attachment.actor.callerPreview, "Object",
     "The visible item's caller has the expected value.");
 
-  let secondRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const secondRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
 
   SnapshotsListView._onRecordButtonClick();

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-stack-01.js

@@ -12,23 +12,23 @@ registerCleanupFunction(function() {
 });
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated]);
 
-  let callItem = CallsListView.getItemAtIndex(2);
-  let locationLink = $(".call-item-location", callItem.target);
+  const callItem = CallsListView.getItemAtIndex(2);
+  const locationLink = $(".call-item-location", callItem.target);
 
   is($(".call-item-stack", callItem.target), null,
     "There should be no stack container available yet for the draw call.");
 
-  let callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
+  const callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
   EventUtils.sendMouseEvent({ type: "mousedown" }, locationLink, window);
   await callStackDisplayed;
 
@@ -65,12 +65,12 @@ async function ifTestingSupported() {
     "doc_simple-canvas-deep-stack.html:35",
     "The fourth function on the stack has the correct location.");
 
-  let jumpedToSource = once(window, EVENTS.SOURCE_SHOWN_IN_JS_DEBUGGER);
+  const jumpedToSource = once(window, EVENTS.SOURCE_SHOWN_IN_JS_DEBUGGER);
   EventUtils.sendMouseEvent({ type: "mousedown" }, $(".call-item-stack-fn-location", callItem.target));
   await jumpedToSource;
 
-  let toolbox = await gDevTools.getToolbox(target);
-  let { panelWin: { DebuggerView: view } } = toolbox.getPanel("jsdebugger");
+  const toolbox = await gDevTools.getToolbox(target);
+  const { panelWin: { DebuggerView: view } } = toolbox.getPanel("jsdebugger");
 
   is(view.Sources.selectedValue, getSourceActor(view.Sources, SIMPLE_CANVAS_DEEP_STACK_URL),
     "The expected source was shown in the debugger.");

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-stack-02.js

@@ -13,23 +13,23 @@ registerCleanupFunction(function() {
 });
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated]);
 
-  let callItem = CallsListView.getItemAtIndex(2);
-  let locationLink = $(".call-item-location", callItem.target);
+  const callItem = CallsListView.getItemAtIndex(2);
+  const locationLink = $(".call-item-location", callItem.target);
 
   is($(".call-item-stack", callItem.target), null,
     "There should be no stack container available yet for the draw call.");
 
-  let callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
+  const callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
   EventUtils.sendMouseEvent({ type: "mousedown" }, locationLink, window);
   await callStackDisplayed;
 
@@ -40,12 +40,12 @@ async function ifTestingSupported() {
   ok($all(".call-item-stack-fn", callItem.target).length >= 4,
      "There should be at least 4 functions on the stack for the draw call.");
 
-  let jumpedToSource = once(window, EVENTS.SOURCE_SHOWN_IN_JS_DEBUGGER);
+  const jumpedToSource = once(window, EVENTS.SOURCE_SHOWN_IN_JS_DEBUGGER);
   EventUtils.sendMouseEvent({ type: "mousedown" }, $(".call-item-location", callItem.target));
   await jumpedToSource;
 
-  let toolbox = await gDevTools.getToolbox(target);
-  let { panelWin: { DebuggerView: view } } = toolbox.getPanel("jsdebugger");
+  const toolbox = await gDevTools.getToolbox(target);
+  const { panelWin: { DebuggerView: view } } = toolbox.getPanel("jsdebugger");
 
   is(view.Sources.selectedValue, getSourceActor(view.Sources, SIMPLE_CANVAS_DEEP_STACK_URL),
     "The expected source was shown in the debugger.");

devtools/client/canvasdebugger/test/browser_canvas-frontend-call-stack-03.js

@@ -7,19 +7,19 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_DEEP_STACK_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated]);
 
-  let callItem = CallsListView.getItemAtIndex(2);
-  let view = $(".call-item-view", callItem.target);
-  let contents = $(".call-item-contents", callItem.target);
+  const callItem = CallsListView.getItemAtIndex(2);
+  const view = $(".call-item-view", callItem.target);
+  const contents = $(".call-item-contents", callItem.target);
 
   is(view.hasAttribute("call-stack-populated"), false,
     "The call item's view should not have the stack populated yet.");
@@ -28,7 +28,7 @@ async function ifTestingSupported() {
   is($(".call-item-stack", callItem.target), null,
     "There should be no stack container available yet for the draw call.");
 
-  let callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
+  const callStackDisplayed = once(window, EVENTS.CALL_STACK_DISPLAYED);
   EventUtils.sendMouseEvent({ type: "dblclick" }, contents, window);
   await callStackDisplayed;
 

devtools/client/canvasdebugger/test/browser_canvas-frontend-clear.js

@@ -6,12 +6,12 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, EVENTS, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, EVENTS, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
-  let firstRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const firstRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   SnapshotsListView._onRecordButtonClick();
 
   await firstRecordingFinished;
@@ -20,7 +20,7 @@ async function ifTestingSupported() {
   is(SnapshotsListView.itemCount, 1,
     "There should be one item available in the snapshots list.");
 
-  let secondRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const secondRecordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   SnapshotsListView._onRecordButtonClick();
 
   await secondRecordingFinished;
@@ -29,7 +29,7 @@ async function ifTestingSupported() {
   is(SnapshotsListView.itemCount, 2,
     "There should be two items available in the snapshots list.");
 
-  let clearingFinished = once(window, EVENTS.SNAPSHOTS_LIST_CLEARED);
+  const clearingFinished = once(window, EVENTS.SNAPSHOTS_LIST_CLEARED);
   SnapshotsListView._onClearButtonClick();
 
   await clearingFinished;

devtools/client/canvasdebugger/test/browser_canvas-frontend-img-screenshots.js

@@ -6,14 +6,14 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
-  let screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated, screenshotDisplayed]);
 

devtools/client/canvasdebugger/test/browser_canvas-frontend-img-thumbnails-01.js

@@ -6,21 +6,21 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
-  let thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([recordingFinished, callListPopulated, thumbnailsDisplayed]);
 
   is($all(".filmstrip-thumbnail").length, 4,
     "There should be 4 thumbnails displayed in the UI.");
 
-  let firstThumbnail = $(".filmstrip-thumbnail[index='0']");
+  const firstThumbnail = $(".filmstrip-thumbnail[index='0']");
   ok(firstThumbnail,
     "The first thumbnail element should be for the function call at index 0.");
   is(firstThumbnail.width, 50,
@@ -30,7 +30,7 @@ async function ifTestingSupported() {
   is(firstThumbnail.getAttribute("flipped"), "false",
     "The first thumbnail should not be flipped vertically.");
 
-  let secondThumbnail = $(".filmstrip-thumbnail[index='2']");
+  const secondThumbnail = $(".filmstrip-thumbnail[index='2']");
   ok(secondThumbnail,
     "The second thumbnail element should be for the function call at index 2.");
   is(secondThumbnail.width, 50,
@@ -40,7 +40,7 @@ async function ifTestingSupported() {
   is(secondThumbnail.getAttribute("flipped"), "false",
     "The second thumbnail should not be flipped vertically.");
 
-  let thirdThumbnail = $(".filmstrip-thumbnail[index='4']");
+  const thirdThumbnail = $(".filmstrip-thumbnail[index='4']");
   ok(thirdThumbnail,
     "The third thumbnail element should be for the function call at index 4.");
   is(thirdThumbnail.width, 50,
@@ -50,7 +50,7 @@ async function ifTestingSupported() {
   is(thirdThumbnail.getAttribute("flipped"), "false",
     "The third thumbnail should not be flipped vertically.");
 
-  let fourthThumbnail = $(".filmstrip-thumbnail[index='6']");
+  const fourthThumbnail = $(".filmstrip-thumbnail[index='6']");
   ok(fourthThumbnail,
     "The fourth thumbnail element should be for the function call at index 6.");
   is(fourthThumbnail.width, 50,

devtools/client/canvasdebugger/test/browser_canvas-frontend-img-thumbnails-02.js

@@ -7,15 +7,15 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
-  let thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
-  let screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
+  const screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([
     recordingFinished,

devtools/client/canvasdebugger/test/browser_canvas-frontend-open.js

@@ -6,8 +6,8 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { $ } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { $ } = panel.panelWin;
 
   is($("#snapshots-pane").hasAttribute("hidden"), false,
     "The snapshots pane should initially be visible.");

devtools/client/canvasdebugger/test/browser_canvas-frontend-record-01.js

@@ -6,8 +6,8 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, EVENTS, $, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, EVENTS, $, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
@@ -23,8 +23,8 @@ async function ifTestingSupported() {
   is(SnapshotsListView.selectedIndex, -1,
     "There should be no selected item in the snapshots list view.");
 
-  let recordingStarted = once(window, EVENTS.SNAPSHOT_RECORDING_STARTED);
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const recordingStarted = once(window, EVENTS.SNAPSHOT_RECORDING_STARTED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   SnapshotsListView._onRecordButtonClick();
 
   await recordingStarted;

devtools/client/canvasdebugger/test/browser_canvas-frontend-record-02.js

@@ -6,20 +6,20 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, EVENTS, L10N, $, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, EVENTS, L10N, $, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingStarted = once(window, EVENTS.SNAPSHOT_RECORDING_STARTED);
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let recordingSelected = once(window, EVENTS.SNAPSHOT_RECORDING_SELECTED);
+  const recordingStarted = once(window, EVENTS.SNAPSHOT_RECORDING_STARTED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const recordingSelected = once(window, EVENTS.SNAPSHOT_RECORDING_SELECTED);
   SnapshotsListView._onRecordButtonClick();
 
   await recordingStarted;
   ok(true, "Started recording a snapshot of the animation loop.");
 
-  let item = SnapshotsListView.getItemAtIndex(0);
+  const item = SnapshotsListView.getItemAtIndex(0);
 
   is($(".snapshot-item-title", item.target).getAttribute("value"),
     L10N.getFormatStr("snapshotsList.itemLabel", 1),

devtools/client/canvasdebugger/test/browser_canvas-frontend-record-03.js

@@ -7,18 +7,18 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, EVENTS, $, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, EVENTS, $, SnapshotsListView } = panel.panelWin;
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   SnapshotsListView._onRecordButtonClick();
 
   await recordingFinished;
   ok(true, "Finished recording a snapshot of the animation loop.");
 
-  let item = SnapshotsListView.getItemAtIndex(0);
+  const item = SnapshotsListView.getItemAtIndex(0);
 
   is(SnapshotsListView.selectedItem, item,
     "The first item should now be selected in the snapshots list view (1).");

devtools/client/canvasdebugger/test/browser_canvas-frontend-record-04.js

@@ -9,13 +9,13 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(RAF_BEGIN_URL);
-  let { window, EVENTS, gFront, SnapshotsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(RAF_BEGIN_URL);
+  const { window, EVENTS, gFront, SnapshotsListView } = panel.panelWin;
   loadFrameScriptUtils();
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
   SnapshotsListView._onRecordButtonClick();
 
   // Wait until after the recording started to trigger the content.

devtools/client/canvasdebugger/test/browser_canvas-frontend-reload-01.js

@@ -6,11 +6,11 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS } = panel.panelWin;
 
-  let reset = once(window, EVENTS.UI_RESET);
-  let navigated = reload(target);
+  const reset = once(window, EVENTS.UI_RESET);
+  const navigated = reload(target);
 
   await reset;
   ok(true, "The UI was reset after the refresh button was clicked.");

devtools/client/canvasdebugger/test/browser_canvas-frontend-reload-02.js

@@ -6,8 +6,8 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, $all, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   is(SnapshotsListView.itemCount, 0,
     "There should be no snapshots initially displayed in the UI.");
@@ -23,10 +23,10 @@ async function ifTestingSupported() {
 
   await reload(target);
 
-  let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-  let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
-  let thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
-  let screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
+  const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+  const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+  const thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
+  const screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
   SnapshotsListView._onRecordButtonClick();
   await Promise.all([
     recordingFinished,
@@ -47,8 +47,8 @@ async function ifTestingSupported() {
   is($all(".filmstrip-thumbnail").length, 4,
     "All the thumbnails should now be displayed in the UI (2).");
 
-  let reset = once(window, EVENTS.UI_RESET);
-  let navigated = reload(target);
+  const reset = once(window, EVENTS.UI_RESET);
+  const navigated = reload(target);
 
   await reset;
   ok(true, "The UI was reset after the refresh button was clicked.");

devtools/client/canvasdebugger/test/browser_canvas-frontend-snapshot-select-01.js

@@ -7,8 +7,8 @@
  */
 
 async function ifTestingSupported() {
-  let { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
-  let { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
+  const { target, panel } = await initCanvasDebuggerFrontend(SIMPLE_CANVAS_URL);
+  const { window, $, EVENTS, SnapshotsListView, CallsListView } = panel.panelWin;
 
   await reload(target);
 
@@ -28,7 +28,7 @@ async function ifTestingSupported() {
   is(CallsListView.selectedIndex, -1,
     "There should still be no call item automatically selected in the snapshot.");
 
-  let secondSnapshotTarget = SnapshotsListView.getItemAtIndex(1).target;
+  const secondSnapshotTarget = SnapshotsListView.getItemAtIndex(1).target;
   let snapshotSelected = waitForSnapshotSelection();
   EventUtils.sendMouseEvent({ type: "mousedown" }, secondSnapshotTarget, window);
 
@@ -40,8 +40,8 @@ async function ifTestingSupported() {
   is(CallsListView.selectedIndex, -1,
     "There should still be no call item automatically selected in the snapshot.");
 
-  let firstDrawCallContents = $(".call-item-contents", CallsListView.getItemAtIndex(2).target);
-  let screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
+  const firstDrawCallContents = $(".call-item-contents", CallsListView.getItemAtIndex(2).target);
+  const screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
   EventUtils.sendMouseEvent({ type: "mousedown" }, firstDrawCallContents, window);
 
   await screenshotDisplayed;
@@ -52,7 +52,7 @@ async function ifTestingSupported() {
   is(CallsListView.selectedIndex, 2,
     "The first draw call should now be selected in the snapshot.");
 
-  let firstSnapshotTarget = SnapshotsListView.getItemAtIndex(0).target;
+  const firstSnapshotTarget = SnapshotsListView.getItemAtIndex(0).target;
   snapshotSelected = waitForSnapshotSelection();
   EventUtils.sendMouseEvent({ type: "mousedown" }, firstSnapshotTarget, window);
 
@@ -65,22 +65,22 @@ async function ifTestingSupported() {
     "There should still be no call item automatically selected in the snapshot.");
 
   function recordAndWaitForFirstSnapshot() {
-    let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
-    let snapshotSelected = waitForSnapshotSelection();
+    const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+    const snapshotSelected = waitForSnapshotSelection();
     SnapshotsListView._onRecordButtonClick();
     return Promise.all([recordingFinished, snapshotSelected]);
   }
 
   function recordAndWaitForAnotherSnapshot() {
-    let recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
+    const recordingFinished = once(window, EVENTS.SNAPSHOT_RECORDING_FINISHED);
     SnapshotsListView._onRecordButtonClick();
     return recordingFinished;
   }
 
   function waitForSnapshotSelection() {
-    let callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
-    let thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
-    let screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
+    const callListPopulated = once(window, EVENTS.CALL_LIST_POPULATED);
+    const thumbnailsDisplayed = once(window, EVENTS.THUMBNAILS_DISPLAYED);
+    const screenshotDisplayed = once(window, EVENTS.CALL_SCREENSHOT_DISPLAYED);
     return Promise.all([
       callListPopulated,
       thumbnailsDisplayed,