CrOS GMC: Hide media notification if GMC for CrOS is enabled.

Bug: 1132904
Change-Id: If39e460248f4358002f1d05c76a32a24d3a0d154
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2435747Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Tommy Steimel <steimel@chromium.org>
Commit-Queue: Jazz Xu <jazzhsu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811283}

ash/shell.cc

@@ -183,6 +183,7 @@
 #include "components/prefs/pref_service.h"
 #include "components/viz/host/host_frame_sink_manager.h"
 #include "dbus/bus.h"
+#include "media/base/media_switches.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/layout_manager.h"
@@ -1218,7 +1219,8 @@ void Shell::Init(
   // is started.
   display_manager_->CreateMirrorWindowAsyncIfAny();
 
-  if (base::FeatureList::IsEnabled(features::kMediaSessionNotification)) {
+  if (base::FeatureList::IsEnabled(features::kMediaSessionNotification) &&
+      !base::FeatureList::IsEnabled(media::kGlobalMediaControlsForChromeOS)) {
     media_notification_controller_ =
         std::make_unique<MediaNotificationControllerImpl>();
   }