Bug 1249281 - add UITelemetry for tab audio mute control, r=gijs

MozReview-Commit-ID: 8UTh7C6EXKL

browser/base/content/tabbrowser.xml

@@ -6243,9 +6243,11 @@
           if (browser.audioMuted) {
             browser.unmute();
             this.removeAttribute("muted");
+            BrowserUITelemetry.countTabMutingEvent("unmute", aMuteReason);
           } else {
             browser.mute();
             this.setAttribute("muted", "true");
+            BrowserUITelemetry.countTabMutingEvent("mute", aMuteReason);
           }
           this.muteReason = aMuteReason || null;
           tabContainer.tabbrowser._tabAttrModified(this, ["muted"]);

browser/modules/BrowserUITelemetry.jsm

@@ -134,6 +134,7 @@ XPCOMUtils.defineLazyGetter(this, "ALL_BUILTIN_ITEMS", function() {
     "BMB_unsortedBookmarksPopup",
     "BMB_bookmarksToolbarPopup",
     "search-go-button",
+    "soundplaying-icon",
   ]
   return DEFAULT_ITEMS.concat(PALETTE_ITEMS)
                       .concat(SPECIAL_CASES);
@@ -610,6 +611,10 @@ this.BrowserUITelemetry = {
     this._countEvent(["forget-button", timeId]);
   },
 
+  countTabMutingEvent: function(action, reason) {
+    this._countEvent(["tab-audio-control", action, reason || "no reason given"]);
+  },
+
   _logAwesomeBarSearchResult: function (url) {
     let spec = Services.search.parseSubmissionURL(url);
     if (spec.engine) {