Bug 1235061 - Create histogram probe to measure how often users have zoomed view enabled/disabled. r=mfinkle p=vladan

--HG--
extra : commitid : KD4RdbOwTZO
extra : rebase_source : 43607b5dfce37c495578fdd62e39802061fd5577
extra : amend_source : 80b97e3d2fa0de7c39fe55665b24ae9918eb78e8

mobile/android/chrome/content/browser.js

@@ -600,10 +600,16 @@ var BrowserApp = {
 
       if (AppConstants.NIGHTLY_BUILD) {
         InitLater(() => ShumwayUtils.init(), window, "ShumwayUtils");
-        InitLater(() => Telemetry.addData("FENNEC_TRACKING_PROTECTION_STATE", parseInt(BrowserApp.getTrackingProtectionState())));
         InitLater(() => WebcompatReporter.init());
       }
 
+      // Collect telemetry data.
+      // We do this at startup because we want to move away from "gather-telemetry" (bug 1127907)
+      InitLater(() => {
+        Telemetry.addData("FENNEC_TRACKING_PROTECTION_STATE", parseInt(BrowserApp.getTrackingProtectionState()));
+        Telemetry.addData("ZOOMED_VIEW_ENABLED", Services.prefs.getBoolPref("ui.zoomedview.enabled"));
+      });
+
       InitLater(() => LightWeightThemeWebInstaller.init());
       InitLater(() => SpatialNavigation.init(BrowserApp.deck, null), window, "SpatialNavigation");
       InitLater(() => CastingApps.init(), window, "CastingApps");

toolkit/components/telemetry/Histograms.json

@@ -8209,6 +8209,13 @@
     "description": "Whether or not a user has tap-to-load enabled.",
     "bug_numbers": [1208167]
   },
+  "ZOOMED_VIEW_ENABLED": {
+    "expires_in_version": "50",
+    "kind": "boolean",
+    "description": "Whether or not a user has the zoomed view (a.k.a. \"Magnify small areas\") enabled.",
+    "alert_emails": ["mobile-frontend@mozilla.com"],
+    "bug_numbers": [1235061]
+  },
   "TRACKING_PROTECTION_ENABLED": {
     "expires_in_version": "never",
     "kind": "boolean",