Remove mutable from rtc::CriticalSection members.

webrtc/modules/video_coding/generic_encoder.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 120 matching lines @@
 
   bool SupportsNativeHandle() const;
 
   int GetTargetFramerate();
 
  private:
   VideoEncoder* const encoder_;
   VideoEncoderRateObserver* const rate_observer_;
   VCMEncodedFrameCallback* const vcm_encoded_frame_callback_;
   const bool internal_source_;
-  mutable rtc::CriticalSection params_lock_;
+  rtc::CriticalSection params_lock_;
   EncoderParameters encoder_params_ GUARDED_BY(params_lock_);
   VideoRotation rotation_;
   bool is_screenshare_;
 };  // end of VCMGenericEncoder class
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_GENERIC_ENCODER_H_