Add UMA to check whether requestAudioFocus() is successful.

content/browser/media/android/media_session_uma_helper.h

 // 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.
 
 #ifndef CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_UMA_HELPER_H_
 #define CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_UMA_HELPER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/time/clock.h"
 #include "content/common/content_export.h"
@@ skipping 14 matching lines @@
     UI = 2,
     CONTENT = 3,
     Count // Leave at the end.
   };
 
   MediaSessionUmaHelper();
   ~MediaSessionUmaHelper();
 
   void RecordSessionSuspended(MediaSessionSuspendedSource source) const;
 
+  // Record the result of calling the native requestAudioFocus().
+  void RecordRequestAudioFocusResult(bool result) const;
+
   void OnSessionActive();
   void OnSessionSuspended();
   void OnSessionInactive();
 
   void SetClockForTest(scoped_ptr<base::Clock> testing_clock);
 
  private:
   base::TimeDelta total_active_time_;
   base::Time current_active_time_;
   scoped_ptr<base::Clock> clock_;
 };
 
 }  // namespace content
 
 #endif // CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_UMA_HELPER_H_