[Android] Fix the issue of muted attribute in video element does not work.

media/base/android/media_player_bridge.h

 // Copyright (c) 2012 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 MEDIA_BASE_ANDROID_MEDIA_PLAYER_BRIDGE_H_
 #define MEDIA_BASE_ANDROID_MEDIA_PLAYER_BRIDGE_H_
 
 #include <jni.h>
 #include <map>
 #include <string>
@@ skipping 158 matching lines @@
   base::android::ScopedJavaGlobalRef<jobject> j_media_player_bridge_;
 
   base::RepeatingTimer<MediaPlayerBridge> time_update_timer_;
 
   // Listener object that listens to all the media player events.
   scoped_ptr<MediaPlayerListener> listener_;
 
   // Whether player is currently using a surface.
   bool is_surface_in_use_;
 
+  // Volume of playback.
+  double volume_;
+
   // Weak pointer passed to |listener_| for callbacks.
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<MediaPlayerBridge> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaPlayerBridge);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_ANDROID_MEDIA_PLAYER_BRIDGE_H_