Remove mutable from rtc::CriticalSections.

webrtc/video/video_capture_input.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 45 matching lines @@
                     EncodingTimeObserver* encoding_time_observer);
   ~VideoCaptureInput();
 
   void IncomingCapturedFrame(const VideoFrame& video_frame) override;
 
  private:
   // Thread functions for deliver captured frames to receivers.
   static bool EncoderThreadFunction(void* obj);
   bool EncoderProcess();
 
-  mutable rtc::CriticalSection crit_;
+  rtc::CriticalSection crit_;
   ProcessThread* const module_process_thread_;
 
   VideoCaptureCallback* const frame_callback_;
   VideoRenderer* const local_renderer_;
   SendStatisticsProxy* const stats_proxy_;
 
   rtc::PlatformThread encoder_thread_;
   rtc::Event capture_event_;
 
   volatile int stop_;
 
   VideoFrame captured_frame_ GUARDED_BY(crit_);
   // Used to make sure incoming time stamp is increasing for every frame.
   int64_t last_captured_timestamp_;
   // Delta used for translating between NTP and internal timestamps.
   const int64_t delta_ntp_internal_ms_;
 
   rtc::scoped_ptr<OveruseFrameDetector> overuse_detector_;
   EncodingTimeObserver* const encoding_time_observer_;
 };
 
 }  // namespace internal
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_VIDEO_CAPTURE_INPUT_H_