Refactor VideoDenoiser to work with I420Buffer, not VideoFrame.

webrtc/common_video/include/video_frame_buffer.h

 /*
  *  Copyright (c) 2015 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 116 matching lines @@
                         int crop_width,
                         int crop_height);
 
   // The common case of a center crop, when needed to adjust the
   // aspect ratio without distorting the image.
   void CropAndScaleFrom(const rtc::scoped_refptr<VideoFrameBuffer>& src);
 
   // Scale all of |src| to the size of |this| buffer, with no cropping.
   void ScaleFrom(const rtc::scoped_refptr<VideoFrameBuffer>& src);
 
+  // Create a new buffer with identical strides, and copy the pixel data.
+  static rtc::scoped_refptr<I420Buffer> CopyKeepStride(
+      const rtc::scoped_refptr<VideoFrameBuffer>& buffer);
+
  protected:
   ~I420Buffer() override;
 
  private:
   const int width_;
   const int height_;
   const int stride_y_;
   const int stride_u_;
   const int stride_v_;
   const std::unique_ptr<uint8_t, AlignedFreeDeleter> data_;
@@ skipping 60 matching lines @@
   const uint8_t* const v_plane_;
   const int y_stride_;
   const int u_stride_;
   const int v_stride_;
   rtc::Callback0<void> no_longer_used_cb_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_FRAME_BUFFER_H_