Refactor VideoDenoiser to work with I420Buffer, not VideoFrame.

webrtc/modules/video_processing/frame_preprocessor.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 43 matching lines @@
 
   // Preprocess output:
   void EnableDenoising(bool enable);
   const VideoFrame* PreprocessFrame(const VideoFrame& frame);
 
  private:
   // The content does not change so much every frame, so to reduce complexity
   // we can compute new content metrics every |kSkipFrameCA| frames.
   enum { kSkipFrameCA = 2 };
 
-  VideoFrame denoised_frame_[2];
+  rtc::scoped_refptr<I420Buffer> denoised_buffer_[2];
+  VideoFrame denoised_frame_;
   VideoFrame resampled_frame_;
   VPMSpatialResampler* spatial_resampler_;
   VPMVideoDecimator* vd_;
   std::unique_ptr<VideoDenoiser> denoiser_;
   uint8_t denoised_frame_toggle_;
   uint32_t frame_cnt_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_PROCESSING_FRAME_PREPROCESSOR_H_