remoting: remove usage of CapturedFrame.elapsed_time in CastVideoCapturerAdapter

remoting/host/cast_video_capturer_adapter.h

 // Copyright 2014 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 REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_
 #define REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_
 
 #include <vector>
 
+#include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "third_party/libjingle/source/talk/media/base/videocapturer.h"
 #include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
@@ skipping 42 matching lines @@
 
   // |thread_checker_| is bound to the peer connection worker thread.
   base::ThreadChecker thread_checker_;
 
   // Used to capture frames.
   scoped_ptr<webrtc::DesktopCapturer> desktop_capturer_;
 
   // Used to schedule periodic screen captures.
   scoped_ptr<base::RepeatingTimer> capture_timer_;
 
-  // Used to set the elapsed_time attribute of captured frames.
-  base::TimeTicks start_time_;
-
   DISALLOW_COPY_AND_ASSIGN(CastVideoCapturerAdapter);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_