Remove mutable from rtc::CriticalSections.

webrtc/video/encoder_state_feedback.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 37 matching lines @@
  protected:
   // Called by EncoderStateFeedbackObserver when a new key frame is requested.
   void OnReceivedIntraFrameRequest(uint32_t ssrc);
   void OnReceivedSLI(uint32_t ssrc, uint8_t picture_id);
   void OnReceivedRPSI(uint32_t ssrc, uint64_t picture_id);
   void OnLocalSsrcChanged(uint32_t old_ssrc, uint32_t new_ssrc);
 
  private:
   typedef std::map<uint32_t,  ViEEncoder*> SsrcEncoderMap;
 
-  mutable rtc::CriticalSection crit_;
+  rtc::CriticalSection crit_;
 
   // Instance registered at the class requesting new key frames.
   rtc::scoped_ptr<EncoderStateFeedbackObserver> observer_;
 
   // Maps a unique ssrc to the given encoder.
   SsrcEncoderMap encoders_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(EncoderStateFeedback);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_ENCODER_STATE_FEEDBACK_H_