diff --git a/browser/components/extensions/ext-bookmarks.js b/browser/components/extensions/ext-bookmarks.js
index bc780a7b233f..35e08436c317 100644
--- a/browser/components/extensions/ext-bookmarks.js
+++ b/browser/components/extensions/ext-bookmarks.js
@@ -77,7 +77,7 @@ function convert(result) {
   return node;
 }
 
-extensions.registerSchemaAPI("bookmarks", (extension, context) => {
+extensions.registerSchemaAPI("bookmarks", context => {
   return {
     bookmarks: {
       get: function(idOrIdList) {
diff --git a/browser/components/extensions/ext-browserAction.js b/browser/components/extensions/ext-browserAction.js
index 94406faefe71..a413380feaa7 100644
--- a/browser/components/extensions/ext-browserAction.js
+++ b/browser/components/extensions/ext-browserAction.js
@@ -259,7 +259,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("browserAction", (extension, context) => {
+extensions.registerSchemaAPI("browserAction", context => {
+  let {extension} = context;
   return {
     browserAction: {
       onClicked: new EventManager(context, "browserAction.onClicked", fire => {
diff --git a/browser/components/extensions/ext-commands.js b/browser/components/extensions/ext-commands.js
index 3fca3dba8e3a..900a7d697081 100644
--- a/browser/components/extensions/ext-commands.js
+++ b/browser/components/extensions/ext-commands.js
@@ -228,7 +228,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("commands", (extension, context) => {
+extensions.registerSchemaAPI("commands", context => {
+  let {extension} = context;
   return {
     commands: {
       getAll() {
diff --git a/browser/components/extensions/ext-contextMenus.js b/browser/components/extensions/ext-contextMenus.js
index 0ad783829791..a263697001b8 100644
--- a/browser/components/extensions/ext-contextMenus.js
+++ b/browser/components/extensions/ext-contextMenus.js
@@ -485,7 +485,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("contextMenus", (extension, context) => {
+extensions.registerSchemaAPI("contextMenus", context => {
+  let {extension} = context;
   return {
     contextMenus: {
       create: function(createProperties, callback) {
diff --git a/browser/components/extensions/ext-history.js b/browser/components/extensions/ext-history.js
index 2180e94116fb..070af53bb5c5 100644
--- a/browser/components/extensions/ext-history.js
+++ b/browser/components/extensions/ext-history.js
@@ -130,7 +130,7 @@ function getObserver() {
   return _observer;
 }
 
-extensions.registerSchemaAPI("history", (extension, context) => {
+extensions.registerSchemaAPI("history", context => {
   return {
     history: {
       addUrl: function(details) {
diff --git a/browser/components/extensions/ext-pageAction.js b/browser/components/extensions/ext-pageAction.js
index 52e8edde6a70..fc817c900bf3 100644
--- a/browser/components/extensions/ext-pageAction.js
+++ b/browser/components/extensions/ext-pageAction.js
@@ -217,7 +217,8 @@ PageAction.for = extension => {
 
 global.pageActionFor = PageAction.for;
 
-extensions.registerSchemaAPI("pageAction", (extension, context) => {
+extensions.registerSchemaAPI("pageAction", context => {
+  let {extension} = context;
   return {
     pageAction: {
       onClicked: new EventManager(context, "pageAction.onClicked", fire => {
diff --git a/browser/components/extensions/ext-tabs.js b/browser/components/extensions/ext-tabs.js
index a0cce53d921b..b2a7a1cf93cb 100644
--- a/browser/components/extensions/ext-tabs.js
+++ b/browser/components/extensions/ext-tabs.js
@@ -264,7 +264,8 @@ let tabListener = {
   },
 };
 
-extensions.registerSchemaAPI("tabs", (extension, context) => {
+extensions.registerSchemaAPI("tabs", context => {
+  let {extension} = context;
   let self = {
     tabs: {
       onActivated: new WindowEventManager(context, "tabs.onActivated", "TabSelect", (fire, event) => {
diff --git a/browser/components/extensions/ext-windows.js b/browser/components/extensions/ext-windows.js
index 1a9d2ece816b..9dfa17578540 100644
--- a/browser/components/extensions/ext-windows.js
+++ b/browser/components/extensions/ext-windows.js
@@ -15,7 +15,8 @@ var {
   EventManager,
 } = ExtensionUtils;
 
-extensions.registerSchemaAPI("windows", (extension, context) => {
+extensions.registerSchemaAPI("windows", context => {
+  let {extension} = context;
   return {
     windows: {
       onCreated:
diff --git a/mobile/android/components/extensions/ext-pageAction.js b/mobile/android/components/extensions/ext-pageAction.js
index 41b99f5106de..12de24383396 100644
--- a/mobile/android/components/extensions/ext-pageAction.js
+++ b/mobile/android/components/extensions/ext-pageAction.js
@@ -117,7 +117,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("pageAction", (extension, context) => {
+extensions.registerSchemaAPI("pageAction", context => {
+  let {extension} = context;
   return {
     pageAction: {
       onClicked: new SingletonEventManager(context, "pageAction.onClicked", fire => {
diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index 5279267796ef..475b0e18283c 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -187,7 +187,7 @@ var Management = {
 
   // Mash together into a single object all the APIs registered by the
   // functions above. Return the merged object.
-  generateAPIs(extension, context, apis, namespaces = null) {
+  generateAPIs(context, apis, namespaces = null) {
     let obj = {};
 
     // Recursively copy properties from source to dest.
@@ -210,16 +210,16 @@ var Management = {
         continue;
       }
       if (api.permission) {
-        if (!extension.hasPermission(api.permission)) {
+        if (!context.extension.hasPermission(api.permission)) {
           continue;
         }
       }
 
-      api = api.api(extension, context);
+      api = api.api(context);
       copy(obj, api);
     }
 
-    for (let api of extension.apis) {
+    for (let api of context.extension.apis) {
       copy(obj, api.getAPI(context));
     }
 
@@ -254,10 +254,9 @@ var Management = {
 // |incognito| is the content running in a private context (default: false).
 ExtensionContext = class extends BaseContext {
   constructor(extension, params) {
-    super(extension.id);
+    super(extension);
 
     let {type, uri} = params;
-    this.extension = extension;
     this.type = type;
     this.uri = uri || extension.baseURI;
     this.incognito = params.incognito || false;
@@ -335,7 +334,7 @@ class ProxyContext extends ExtensionContext {
     this.principal_ = principal;
 
     this.apiObj = {};
-    GlobalManager.injectInObject(extension, this, null, this.apiObj, ["storage", "test"]);
+    GlobalManager.injectInObject(this, null, this.apiObj, ["storage", "test"]);
 
     this.listenerProxies = new Map();
 
@@ -635,11 +634,11 @@ GlobalManager = {
     return this.extensionMap.get(extensionId);
   },
 
-  injectInObject(extension, context, defaultCallback, dest, namespaces = null) {
-    let api = Management.generateAPIs(extension, context, Management.apis, namespaces);
+  injectInObject(context, defaultCallback, dest, namespaces = null) {
+    let api = Management.generateAPIs(context, Management.apis, namespaces);
     injectAPI(api, dest);
 
-    let schemaApi = Management.generateAPIs(extension, context, Management.schemaApis, namespaces);
+    let schemaApi = Management.generateAPIs(context, Management.schemaApis, namespaces);
 
     // Add in any extra API namespaces which do not have implementations
     // outside of their schema file.
@@ -655,7 +654,7 @@ GlobalManager = {
       },
 
       hasPermission(permission) {
-        return extension.hasPermission(permission);
+        return context.extension.hasPermission(permission);
       },
 
       callFunction(path, name, args) {
@@ -718,14 +717,14 @@ GlobalManager = {
       return;
     }
 
-    let inject = (extension, context) => {
+    let inject = context => {
       // We create two separate sets of bindings, one for the `chrome`
       // global, and one for the `browser` global. The latter returns
       // Promise objects if a callback is not passed, while the former
       // does not.
       let injectObject = (name, defaultCallback) => {
         let browserObj = Cu.createObjectIn(contentWindow, {defineAs: name});
-        this.injectInObject(extension, context, defaultCallback, browserObj);
+        this.injectInObject(context, defaultCallback, browserObj);
       };
 
       injectObject("browser", null);
@@ -774,7 +773,7 @@ GlobalManager = {
     let incognito = PrivateBrowsingUtils.isContentWindowPrivate(contentWindow);
 
     let context = new ExtensionContext(extension, {type, contentWindow, uri, docShell, incognito});
-    inject(extension, context);
+    inject(context);
     if (type == "background") {
       this._initializeBackgroundPage(contentWindow);
     }
diff --git a/toolkit/components/extensions/ExtensionContent.jsm b/toolkit/components/extensions/ExtensionContent.jsm
index 0bdeaca25c31..51fe36ce0599 100644
--- a/toolkit/components/extensions/ExtensionContent.jsm
+++ b/toolkit/components/extensions/ExtensionContent.jsm
@@ -312,14 +312,12 @@ var ExtensionManager;
 // Cu.Sandbox to run the code. There is a separate scope for each
 // frame.
 class ExtensionContext extends BaseContext {
-  constructor(extensionId, contentWindow, contextOptions = {}) {
-    super(extensionId);
+  constructor(extension, contentWindow, contextOptions = {}) {
+    super(extension);
 
     let {isExtensionPage} = contextOptions;
 
     this.isExtensionPage = isExtensionPage;
-    this.extension = ExtensionManager.get(extensionId);
-    this.extensionId = extensionId;
 
     this.setContentWindow(contentWindow);
 
@@ -338,7 +336,7 @@ class ExtensionContext extends BaseContext {
     // copy origin attributes from the content window origin attributes to
     // preserve the user context id. overwrite the addonId.
     let attrs = contentPrincipal.originAttributes;
-    attrs.addonId = extensionId;
+    attrs.addonId = this.extensionId;
     let extensionPrincipal = ssm.createCodebasePrincipal(this.extension.baseURI, attrs);
     Object.defineProperty(this, "principal",
                           {value: extensionPrincipal, enumerable: true, configurable: true});
@@ -352,7 +350,7 @@ class ExtensionContext extends BaseContext {
     }
 
     if (isExtensionPage) {
-      if (ExtensionManagement.getAddonIdForWindow(this.contentWindow) != extensionId) {
+      if (ExtensionManagement.getAddonIdForWindow(this.contentWindow) != this.extensionId) {
         throw new Error("Invalid target window for this extension context");
       }
       // This is an iframe with content script API enabled and its principal should be the
@@ -400,7 +398,7 @@ class ExtensionContext extends BaseContext {
     let sender = {id: this.extension.uuid, frameId, url};
     // Properties in |filter| must match those in the |recipient|
     // parameter of sendMessage.
-    let filter = {extensionId, frameId};
+    let filter = {extensionId: this.extensionId, frameId};
     this.messenger = new Messenger(this, [mm], sender, filter, delegate);
 
     this.chromeObj = Cu.createObjectIn(this.sandbox, {defineAs: "browser"});
@@ -532,9 +530,11 @@ DocumentManager = {
       const {CONTENTSCRIPT_PRIVILEGES} = ExtensionManagement.API_LEVELS;
       let extensionId = ExtensionManagement.getAddonIdForWindow(window);
 
-      if (ExtensionManagement.getAPILevelForWindow(window, extensionId) == CONTENTSCRIPT_PRIVILEGES &&
-          ExtensionManager.get(extensionId)) {
-        DocumentManager.getExtensionPageContext(extensionId, window);
+      if (ExtensionManagement.getAPILevelForWindow(window, extensionId) == CONTENTSCRIPT_PRIVILEGES) {
+        let extension = ExtensionManager.get(extensionId);
+        if (extension) {
+          DocumentManager.getExtensionPageContext(extension, window);
+        }
       }
 
       this.trigger("document_start", window);
@@ -594,7 +594,7 @@ DocumentManager = {
       let script = new Script(extension, options, deferred);
 
       if (script.matches(window)) {
-        let context = this.getContentScriptContext(extensionId, window);
+        let context = this.getContentScriptContext(extension, window);
         context.addScript(script);
         return deferred.promise;
       }
@@ -642,27 +642,27 @@ DocumentManager = {
     return [];
   },
 
-  getContentScriptContext(extensionId, window) {
+  getContentScriptContext(extension, window) {
     let winId = getInnerWindowID(window);
     if (!this.contentScriptWindows.has(winId)) {
       this.contentScriptWindows.set(winId, new Map());
     }
 
     let extensions = this.contentScriptWindows.get(winId);
-    if (!extensions.has(extensionId)) {
-      let context = new ExtensionContext(extensionId, window);
-      extensions.set(extensionId, context);
+    if (!extensions.has(extension.id)) {
+      let context = new ExtensionContext(extension, window);
+      extensions.set(extension.id, context);
     }
 
-    return extensions.get(extensionId);
+    return extensions.get(extension.id);
   },
 
-  getExtensionPageContext(extensionId, window) {
+  getExtensionPageContext(extension, window) {
     let winId = getInnerWindowID(window);
 
     let context = this.extensionPageWindows.get(winId);
     if (!context) {
-      let context = new ExtensionContext(extensionId, window, {isExtensionPage: true});
+      let context = new ExtensionContext(extension, window, {isExtensionPage: true});
       this.extensionPageWindows.set(winId, context);
     }
 
@@ -683,7 +683,7 @@ DocumentManager = {
       for (let window of this.enumerateWindows(global.docShell)) {
         for (let script of extension.scripts) {
           if (script.matches(window)) {
-            let context = this.getContentScriptContext(extensionId, window);
+            let context = this.getContentScriptContext(extension, window);
             context.addScript(script);
           }
         }
@@ -721,10 +721,10 @@ DocumentManager = {
     let state = this.getWindowState(window);
 
     if (state == "document_start") {
-      for (let [extensionId, extension] of ExtensionManager.extensions) {
+      for (let extension of ExtensionManager.extensions.values()) {
         for (let script of extension.scripts) {
           if (script.matches(window)) {
-            let context = this.getContentScriptContext(extensionId, window);
+            let context = this.getContentScriptContext(extension, window);
             context.addScript(script);
           }
         }
diff --git a/toolkit/components/extensions/ExtensionUtils.jsm b/toolkit/components/extensions/ExtensionUtils.jsm
index 2152b9d5c735..fec2d2ef85e3 100644
--- a/toolkit/components/extensions/ExtensionUtils.jsm
+++ b/toolkit/components/extensions/ExtensionUtils.jsm
@@ -162,13 +162,14 @@ class SpreadArgs extends Array {
 let gContextId = 0;
 
 class BaseContext {
-  constructor(extensionId) {
+  constructor(extension) {
     this.onClose = new Set();
     this.checkedLastError = false;
     this._lastError = null;
     this.contextId = `${++gContextId}-${Services.appinfo.uniqueProcessID}`;
     this.unloaded = false;
-    this.extensionId = extensionId;
+    this.extension = extension;
+    this.extensionId = extension.id;
     this.jsonSandbox = null;
     this.active = true;
 
diff --git a/toolkit/components/extensions/ext-alarms.js b/toolkit/components/extensions/ext-alarms.js
index 5e94efc8caff..9a59b9d549d3 100644
--- a/toolkit/components/extensions/ext-alarms.js
+++ b/toolkit/components/extensions/ext-alarms.js
@@ -93,7 +93,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("alarms", (extension, context) => {
+extensions.registerSchemaAPI("alarms", context => {
+  let {extension} = context;
   return {
     alarms: {
       create: function(name, alarmInfo) {
diff --git a/toolkit/components/extensions/ext-backgroundPage.js b/toolkit/components/extensions/ext-backgroundPage.js
index 7fa692356afc..e9ebc87f58c6 100644
--- a/toolkit/components/extensions/ext-backgroundPage.js
+++ b/toolkit/components/extensions/ext-backgroundPage.js
@@ -143,7 +143,8 @@ extensions.on("shutdown", (type, extension) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("extension", (extension, context) => {
+extensions.registerSchemaAPI("extension", context => {
+  let {extension} = context;
   return {
     extension: {
       getBackgroundPage: function() {
diff --git a/toolkit/components/extensions/ext-cookies.js b/toolkit/components/extensions/ext-cookies.js
index 8bbb714a57cb..a941308f0adf 100644
--- a/toolkit/components/extensions/ext-cookies.js
+++ b/toolkit/components/extensions/ext-cookies.js
@@ -238,7 +238,8 @@ function* query(detailsIn, props, extension) {
   }
 }
 
-extensions.registerSchemaAPI("cookies", (extension, context) => {
+extensions.registerSchemaAPI("cookies", context => {
+  let {extension} = context;
   let self = {
     cookies: {
       get: function(details) {
diff --git a/toolkit/components/extensions/ext-downloads.js b/toolkit/components/extensions/ext-downloads.js
index 981e064dbd03..f9123ae72a5d 100644
--- a/toolkit/components/extensions/ext-downloads.js
+++ b/toolkit/components/extensions/ext-downloads.js
@@ -386,7 +386,8 @@ function queryHelper(query) {
   });
 }
 
-extensions.registerSchemaAPI("downloads", (extension, context) => {
+extensions.registerSchemaAPI("downloads", context => {
+  let {extension} = context;
   return {
     downloads: {
       download(options) {
diff --git a/toolkit/components/extensions/ext-extension.js b/toolkit/components/extensions/ext-extension.js
index d2c772e78fc0..3e32d185a5ac 100644
--- a/toolkit/components/extensions/ext-extension.js
+++ b/toolkit/components/extensions/ext-extension.js
@@ -1,6 +1,7 @@
 "use strict";
 
-extensions.registerSchemaAPI("extension", (extension, context) => {
+extensions.registerSchemaAPI("extension", context => {
+  let {extension} = context;
   return {
     extension: {
       getURL: function(url) {
diff --git a/toolkit/components/extensions/ext-i18n.js b/toolkit/components/extensions/ext-i18n.js
index c1c57d922e8e..f6d80724567e 100644
--- a/toolkit/components/extensions/ext-i18n.js
+++ b/toolkit/components/extensions/ext-i18n.js
@@ -7,7 +7,8 @@ var {
   detectLanguage,
 } = ExtensionUtils;
 
-extensions.registerSchemaAPI("i18n", (extension, context) => {
+extensions.registerSchemaAPI("i18n", context => {
+  let {extension} = context;
   return {
     i18n: {
       getMessage: function(messageName, substitutions) {
diff --git a/toolkit/components/extensions/ext-idle.js b/toolkit/components/extensions/ext-idle.js
index fa948f3cea0d..2a9023145690 100644
--- a/toolkit/components/extensions/ext-idle.js
+++ b/toolkit/components/extensions/ext-idle.js
@@ -1,6 +1,6 @@
 "use strict";
 
-extensions.registerSchemaAPI("idle", (extension, context) => {
+extensions.registerSchemaAPI("idle", context => {
   return {
     idle: {
       queryState: function(detectionIntervalInSeconds) {
diff --git a/toolkit/components/extensions/ext-management.js b/toolkit/components/extensions/ext-management.js
index da863017fac7..70e67ae3aa81 100644
--- a/toolkit/components/extensions/ext-management.js
+++ b/toolkit/components/extensions/ext-management.js
@@ -2,7 +2,7 @@
 /* vim: set sts=2 sw=2 et tw=80: */
 "use strict";
 
-extensions.registerSchemaAPI("management", (extension, context) => {
+extensions.registerSchemaAPI("management", context => {
   return {
     management: {},
   };
diff --git a/toolkit/components/extensions/ext-notifications.js b/toolkit/components/extensions/ext-notifications.js
index 8bae71ef1fe1..7e8912c6b476 100644
--- a/toolkit/components/extensions/ext-notifications.js
+++ b/toolkit/components/extensions/ext-notifications.js
@@ -92,7 +92,8 @@ extensions.on("shutdown", (type, extension) => {
 
 var nextId = 0;
 
-extensions.registerSchemaAPI("notifications", (extension, context) => {
+extensions.registerSchemaAPI("notifications", context => {
+  let {extension} = context;
   return {
     notifications: {
       create: function(notificationId, options) {
diff --git a/toolkit/components/extensions/ext-runtime.js b/toolkit/components/extensions/ext-runtime.js
index 924f1a041dc2..803e91179ea3 100644
--- a/toolkit/components/extensions/ext-runtime.js
+++ b/toolkit/components/extensions/ext-runtime.js
@@ -20,7 +20,8 @@ var {
 XPCOMUtils.defineLazyModuleGetter(this, "NativeApp",
                                   "resource://gre/modules/NativeMessaging.jsm");
 
-extensions.registerSchemaAPI("runtime", (extension, context) => {
+extensions.registerSchemaAPI("runtime", context => {
+  let {extension} = context;
   return {
     runtime: {
       onStartup: new EventManager(context, "runtime.onStartup", fire => {
diff --git a/toolkit/components/extensions/ext-storage.js b/toolkit/components/extensions/ext-storage.js
index 1293efadb06d..bf03262b6a39 100644
--- a/toolkit/components/extensions/ext-storage.js
+++ b/toolkit/components/extensions/ext-storage.js
@@ -10,7 +10,8 @@ var {
   EventManager,
 } = ExtensionUtils;
 
-extensions.registerSchemaAPI("storage", (extension, context) => {
+extensions.registerSchemaAPI("storage", context => {
+  let {extension} = context;
   return {
     storage: {
       local: {
diff --git a/toolkit/components/extensions/ext-test.js b/toolkit/components/extensions/ext-test.js
index 80ad28b61bc1..485e14aeb06f 100644
--- a/toolkit/components/extensions/ext-test.js
+++ b/toolkit/components/extensions/ext-test.js
@@ -25,7 +25,8 @@ extensions.on("test-message", (type, extension, ...args) => {
 });
 /* eslint-enable mozilla/balanced-listeners */
 
-extensions.registerSchemaAPI("test", (extension, context) => {
+extensions.registerSchemaAPI("test", context => {
+  let {extension} = context;
   return {
     test: {
       sendMessage: function(...args) {
diff --git a/toolkit/components/extensions/ext-webNavigation.js b/toolkit/components/extensions/ext-webNavigation.js
index b72487bbff46..91ecfdf2f329 100644
--- a/toolkit/components/extensions/ext-webNavigation.js
+++ b/toolkit/components/extensions/ext-webNavigation.js
@@ -158,7 +158,7 @@ function convertGetFrameResult(tabId, data) {
   };
 }
 
-extensions.registerSchemaAPI("webNavigation", (extension, context) => {
+extensions.registerSchemaAPI("webNavigation", context => {
   return {
     webNavigation: {
       onBeforeNavigate: new WebNavigationEventManager(context, "onBeforeNavigate").api(),
diff --git a/toolkit/components/extensions/ext-webRequest.js b/toolkit/components/extensions/ext-webRequest.js
index 6589ec7bfb44..60cbc66ea9a4 100644
--- a/toolkit/components/extensions/ext-webRequest.js
+++ b/toolkit/components/extensions/ext-webRequest.js
@@ -99,7 +99,7 @@ function WebRequestEventManager(context, eventName) {
 
 WebRequestEventManager.prototype = Object.create(SingletonEventManager.prototype);
 
-extensions.registerSchemaAPI("webRequest", (extension, context) => {
+extensions.registerSchemaAPI("webRequest", context => {
   return {
     webRequest: {
       onBeforeRequest: new WebRequestEventManager(context, "onBeforeRequest").api(),
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_context.html b/toolkit/components/extensions/test/mochitest/test_ext_contentscript_context.html
index ca19a877dd5b..ac178b7d7634 100644
--- a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_context.html
+++ b/toolkit/components/extensions/test/mochitest/test_ext_contentscript_context.html
@@ -49,7 +49,7 @@ add_task(function* test_contentscript_context() {
   // Get the content script context and check that it points to the correct window.
 
   let {DocumentManager} = SpecialPowers.Cu.import("resource://gre/modules/ExtensionContent.jsm", {});
-  let context = DocumentManager.getContentScriptContext(extension.id, win);
+  let context = DocumentManager.getContentScriptContext(extension, win);
   ok(context != null, "Got content script context");
 
   is(SpecialPowers.unwrap(context.contentWindow), win, "Context's contentWindow property is correct");
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_contexts.js b/toolkit/components/extensions/test/xpcshell/test_ext_contexts.js
index c54638530ba4..2ac1daeba106 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_contexts.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_contexts.js
@@ -13,16 +13,13 @@ var {
 
 class StubContext extends BaseContext {
   constructor() {
-    super();
+    let fakeExtension = {id: "test@web.extension"};
+    super(fakeExtension);
     this.sandbox = Cu.Sandbox(global);
   }
 
   get cloneScope() {
-    return this. sandbox;
-  }
-
-  get extension() {
-    return {id: "test@web.extension"};
+    return this.sandbox;
   }
 }
 
@@ -130,13 +127,13 @@ add_task(function* test_post_unload_listeners() {
 
 class Context extends BaseContext {
   constructor(principal) {
-    super();
+    let fakeExtension = {id: "test@web.extension"};
+    super(fakeExtension);
     Object.defineProperty(this, "principal", {
       value: principal,
       configurable: true,
     });
     this.sandbox = Cu.Sandbox(principal, {wantXrays: false});
-    this.extension = {id: "test@web.extension"};
   }
 
   get cloneScope() {
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_schemas_api_injection.js b/toolkit/components/extensions/test/xpcshell/test_ext_schemas_api_injection.js
index 544f536e5c92..7e380681e0d4 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_schemas_api_injection.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_schemas_api_injection.js
@@ -46,7 +46,7 @@ add_task(function* testSchemaAPIInjection() {
   yield Schemas.load(url);
 
   // Register an API that will skip the background page.
-  Management.registerSchemaAPI("noBackgroundAPI.testnamespace", (extension, context) => {
+  Management.registerSchemaAPI("noBackgroundAPI.testnamespace", context => {
     if (context.type !== "background") {
       return {
         noBackgroundAPI: {
@@ -63,7 +63,7 @@ add_task(function* testSchemaAPIInjection() {
   });
 
   // Register an API that will skip any but the background page.
-  Management.registerSchemaAPI("backgroundAPI.testnamespace", (extension, context) => {
+  Management.registerSchemaAPI("backgroundAPI.testnamespace", context => {
     if (context.type === "background") {
       return {
         backgroundAPI: {