Bug 1412029 - add probes to about:devtools;r=bgrins,datareview=francois

This changeset adds 3 scalars:
- devtools.aboutdevtools.opened -> logged every time the page is loaded
- devtools.aboutdevtools.installed -> logged when the user clicks on the
  install button
- devtools.aboutdevtools.noinstall_exits -> logged when leaving the page
  if devtools is not enabled

And 2 keyed histograms:
- DEVTOOLS_ABOUT_DEVTOOLS_OPENED_REASON (is it a shortcut, is it a menu
  item etc...)
- DEVTOOLS_ABOUT_DEVTOOLS_OPENED_KEY (in case of a keyshortcut, what is
  the keyshortcut id)


MozReview-Commit-ID: 1DET1ozf8i4

--HG--
extra : rebase_source : f2f96e29a8849dec83b03d6daacbf6c6ca7fce2f

devtools/shim/aboutdevtools/aboutdevtools.js

@@ -9,6 +9,12 @@ const { Services } = Cu.import("resource://gre/modules/Services.jsm", {});
 
 const DEVTOOLS_ENABLED_PREF = "devtools.enabled";
 
+const TELEMETRY_OPENED_KEY = "DEVTOOLS_ABOUT_DEVTOOLS_OPENED_KEY";
+const TELEMETRY_OPENED_REASON = "DEVTOOLS_ABOUT_DEVTOOLS_OPENED_REASON";
+const TELEMETRY_OPENED = "devtools.aboutdevtools.opened";
+const TELEMETRY_INSTALLED = "devtools.aboutdevtools.installed";
+const TELEMETRY_NOINSTALL_EXITS = "devtools.aboutdevtools.noinstall_exits";
+
 const MESSAGES = {
   AboutDebugging: "about-debugging-message",
   ContextMenu: "inspect-element-message",
@@ -27,8 +33,12 @@ const keyShortcutsBundle = Services.strings.createBundle(KEY_SHORTCUTS_STRINGS);
 // we have to use http in order to have working searchParams.
 let url = new URL(window.location.href.replace("about:", "http://"));
 let reason = url.searchParams.get("reason");
+let keyid = url.searchParams.get("keyid");
 let tabid = parseInt(url.searchParams.get("tabid"), 10);
 
+// Keep track of the initial devtools.enabled value to track exits in telemetry.
+let isEnabledOnLoad;
+
 function getToolboxShortcut() {
   const modifier = Services.appinfo.OS == "Darwin" ? "Cmd+Opt+" : "Ctrl+Shift+";
   return modifier + keyShortcutsBundle.GetStringFromName("toggleToolbox.commandkey");
@@ -36,6 +46,12 @@ function getToolboxShortcut() {
 
 function onInstallButtonClick() {
   Services.prefs.setBoolPref("devtools.enabled", true);
+
+  try {
+    Services.telemetry.scalarAdd(TELEMETRY_INSTALLED, 1);
+  } catch (e) {
+    dump("about:devtools oninstall telemetry failed: " + e + "\n");
+  }
 }
 
 function onCloseButtonClick() {
@@ -169,6 +185,20 @@ window.addEventListener("load", function () {
 
   // Update the current page based on the current value of DEVTOOLS_ENABLED_PREF.
   updatePage();
+
+  try {
+    if (reason) {
+      Services.telemetry.getHistogramById(TELEMETRY_OPENED_REASON).add(reason);
+    }
+
+    if (keyid) {
+      Services.telemetry.getHistogramById(TELEMETRY_OPENED_KEY).add(keyid);
+    }
+
+    Services.telemetry.scalarAdd(TELEMETRY_OPENED, 1);
+  } catch (e) {
+    dump("about:devtools onload telemetry failed: " + e + "\n");
+  }
 }, { once: true });
 
 window.addEventListener("beforeunload", function () {
@@ -194,4 +224,13 @@ window.addEventListener("unload", function () {
   document.getElementById("install").removeEventListener("click", onInstallButtonClick);
   document.getElementById("close").removeEventListener("click", onCloseButtonClick);
   Services.prefs.removeObserver(DEVTOOLS_ENABLED_PREF, updatePage);
+
+  const isEnabled = Services.prefs.getBoolPref("devtools.enabled");
+  if (!isEnabledOnLoad && !isEnabled) {
+    try {
+      Services.telemetry.scalarAdd(TELEMETRY_NOINSTALL_EXITS, 1);
+    } catch (e) {
+      dump("about:devtools onunload telemetry failed: " + e + "\n");
+    }
+  }
 }, {once: true});

toolkit/components/telemetry/Histograms.json

@@ -8504,6 +8504,24 @@
     "n_buckets": 1000,
     "description": "The time (in milliseconds) that it took to display a selected source to the user."
   },
+  "DEVTOOLS_ABOUT_DEVTOOLS_OPENED_KEY": {
+    "record_in_processes": ["main"],
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org", "hkirschner@mozilla.com"],
+    "bug_numbers": [1412029],
+    "expires_in_version": "60",
+    "kind": "categorical",
+    "labels": ["toggleToolbox", "toggleToolboxF12", "inspector", "webconsole", "jsdebugger", "netmonitor", "toggleToolbar", "webide", "browserToolbox", "browserConsole", "responsiveDesignMode", "scratchpad", "styleeditor", "performance", "storage", "dom"],
+    "description": "Records the key shortcut passed to open the about:devtools page."
+  },
+  "DEVTOOLS_ABOUT_DEVTOOLS_OPENED_REASON": {
+    "record_in_processes": ["main"],
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org", "hkirschner@mozilla.com"],
+    "bug_numbers": [1412029],
+    "expires_in_version": "60",
+    "kind": "categorical",
+    "labels": ["KeyShortcut", "SystemMenu", "HamburgerMenu", "ContextMenu", "CommandLine"],
+    "description": "Records the reason for opening the about:devtools page."
+  },
   "MEDIA_RUST_MP4PARSE_SUCCESS": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["giles@mozilla.com", "kinetik@flim.org"],

toolkit/components/telemetry/Scalars.yaml

@@ -921,6 +921,41 @@ devtools:
     record_in_processes:
       - 'main'
 
+devtools.aboutdevtools:
+  opened:
+    bug_numbers:
+      - 1412029
+    description: >
+      Number of times about:devtools was opened.
+    expires: "60"
+    kind: uint
+    notification_emails:
+      - dev-developer-tools@lists.mozilla.org, jdescottes@mozilla.com
+    record_in_processes:
+      - 'main'
+  installed:
+    bug_numbers:
+      - 1412029
+    description: >
+      Number of times devtools were enabled/installed in about:devtools.
+    expires: "60"
+    kind: uint
+    notification_emails:
+      - dev-developer-tools@lists.mozilla.org, jdescottes@mozilla.com
+    record_in_processes:
+      - 'main'
+  noinstall_exits:
+    bug_numbers:
+      - 1412029
+    description: >
+      Number of times the user left about:devtools without enabling devtools.
+    expires: "60"
+    kind: uint
+    notification_emails:
+      - dev-developer-tools@lists.mozilla.org, jdescottes@mozilla.com
+    record_in_processes:
+      - 'main'
+
 navigator.storage:
   estimate_count:
     bug_numbers: