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

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

Index: chrome/browser/media/router/mojo/media_router_mojo_impl.cc
diff --git a/chrome/browser/media/router/mojo/media_router_mojo_impl.cc b/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
index d7cbb2a1857a9a1af1d2002ccaa49e7618ff8ba1..454d93f330e782edbbff537f9cd579b9c6ebf2f1 100644
--- a/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
+++ b/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
@@ -1099,9 +1099,9 @@ void MediaRouterMojoImpl::RemoveInvalidRouteControllers(
 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