Change blink::WebMediaPlayer::buffered() to return by-value

public/platform/WebMediaPlayer.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 89 matching lines @@
     virtual void load(LoadType, const WebURL&, CORSMode) = 0;
 
     // Playback controls.
     virtual void play() = 0;
     virtual void pause() = 0;
     virtual bool supportsSave() const = 0;
     virtual void seek(double seconds) = 0;
     virtual void setRate(double) = 0;
     virtual void setVolume(double) = 0;
     virtual void setPreload(Preload) { };
-    virtual const WebTimeRanges& buffered() = 0;
+    virtual WebTimeRanges buffered() const = 0;
     virtual double maxTimeSeekable() const = 0;
 
     virtual void paint(WebCanvas*, const WebRect&, unsigned char alpha) = 0;
 
     // True if the loaded media has a playable video/audio track.
     virtual bool hasVideo() const = 0;
     virtual bool hasAudio() const = 0;
 
     // Dimension of the video.
     virtual WebSize naturalSize() const = 0;
@@ skipping 39 matching lines @@
     // Instruct WebMediaPlayer to enter/exit fullscreen.
     virtual void enterFullscreen() { }
     virtual void exitFullscreen() { }
     // Returns true if the player can enter fullscreen.
     virtual bool canEnterFullscreen() const { return false; }
 };
 
 } // namespace blink
 
 #endif