[Media Router] Add UMA metrics for media route controller creation

chrome/browser/media/router/mojo/media_router_mojo_impl.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/media/router/mojo/media_router_mojo_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 1081 matching lines @@
     } else {
       it->second->Invalidate();
       it = route_controllers_.erase(it);
     }
   }
 }
 
 void MediaRouterMojoImpl::OnMediaControllerCreated(
     const MediaRoute::Id& route_id,
     bool success) {
-  // TODO(takumif): Record success/failure with UMA.
   DVLOG_WITH_INSTANCE(1) << "OnMediaControllerCreated: " << route_id
                          << (success ? " was successful." : " failed.");
+  MediaRouterMojoMetrics::RecordMediaRouteControllerCreationResult(success);
 }
 
 }  // namespace media_router