--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -229,18 +229,16 @@ const listeners = {
 // Seconds of idle before trying to create a bookmarks backup.
 const BOOKMARKS_BACKUP_IDLE_TIME_SEC = 8 * 60;
 // Minimum interval between backups.  We try to not create more than one backup
 // per interval.
 const BOOKMARKS_BACKUP_MIN_INTERVAL_DAYS = 1;
 // Maximum interval between backups.  If the last backup is older than these
 // days we will try to create a new one more aggressively.
 const BOOKMARKS_BACKUP_MAX_INTERVAL_DAYS = 3;
-// Seconds of idle time before reporting media telemetry.
-const MEDIA_TELEMETRY_IDLE_TIME_SEC = 20;
 // Seconds of idle time before the late idle tasks will be scheduled.
 const LATE_TASKS_IDLE_TIME_SEC = 20;
 
 // Factory object
 const BrowserGlueServiceFactory = {
   _instance: null,
   createInstance: function BGSF_createInstance(outer, iid) {
     if (outer != null)
@@ -577,20 +575,16 @@ BrowserGlue.prototype = {
     if (this._bookmarksBackupIdleTime) {
       this._idleService.removeIdleObserver(this, this._bookmarksBackupIdleTime);
       delete this._bookmarksBackupIdleTime;
     }
     if (this._lateTasksIdleObserver) {
       this._idleService.removeIdleObserver(this._lateTasksIdleObserver, LATE_TASKS_IDLE_TIME_SEC);
       delete this._lateTasksIdleObserver;
     }
-    if (this._mediaTelemetryIdleObserver) {
-      this._idleService.removeIdleObserver(this._mediaTelemetryIdleObserver, MEDIA_TELEMETRY_IDLE_TIME_SEC);
-      delete this._mediaTelemetryIdleObserver;
-    }
     try {
       os.removeObserver(this, "places-init-complete");
     } catch (ex) { /* Could have been removed already */ }
     os.removeObserver(this, "handle-xul-text-link");
     os.removeObserver(this, "profile-before-change");
     os.removeObserver(this, "keyword-search");
     os.removeObserver(this, "browser-search-engine-modified");
     os.removeObserver(this, "flash-plugin-hang");
@@ -974,37 +968,22 @@ BrowserGlue.prototype = {
     DirectoryLinksProvider.init();
     NewTabUtils.init();
     NewTabUtils.links.addProvider(DirectoryLinksProvider);
 
     PageActions.init();
 
     this._firstWindowTelemetry(aWindow);
     this._firstWindowLoaded();
-
-    this._mediaTelemetryIdleObserver = {
-      browserGlue: this,
-      observe(aSubject, aTopic, aData) {
-        if (aTopic != "idle") {
-          return;
-        }
-        this.browserGlue._sendMediaTelemetry();
-      }
-    };
-    this._idleService.addIdleObserver(this._mediaTelemetryIdleObserver,
-                                      MEDIA_TELEMETRY_IDLE_TIME_SEC);
   },
 
   _sendMediaTelemetry() {
     let win = RecentWindow.getMostRecentBrowserWindow();
     let v = win.document.createElementNS("http://www.w3.org/1999/xhtml", "video");
     v.reportCanPlayTelemetry();
-    this._idleService.removeIdleObserver(this._mediaTelemetryIdleObserver,
-                                         MEDIA_TELEMETRY_IDLE_TIME_SEC);
-    delete this._mediaTelemetryIdleObserver;
   },
 
   /**
    * Application shutdown handler.
    */
   _onQuitApplicationGranted() {
     // This pref must be set here because SessionStore will use its value
     // on quit-application.
@@ -1174,17 +1153,19 @@ BrowserGlue.prototype = {
    * LATE_TASKS_IDLE_TIME_SEC to see the current value for this idle
    * observer.
    *
    * Note: this function may never be called if the user is never idle for the
    * full length of the period of time specified. But given a reasonably low
    * value, this is unlikely.
    */
   _scheduleArbitrarilyLateIdleTasks() {
-    // TODO: Functions to be added here with Services.tm.idleDispatchToMainThread
+    Services.tm.idleDispatchToMainThread(() => {
+      this._sendMediaTelemetry();
+    });
   },
 
   _createExtraDefaultProfile() {
     if (!AppConstants.MOZ_DEV_EDITION) {
       return;
     }
     // If Developer Edition is the only installed Firefox version and no other
     // profiles are present, create a second one for use by other versions.