Update I420Buffer to new VideoFrameBuffer interface

webrtc/examples/peerconnection/client/main_wnd.cc

 /*
  *  Copyright 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 588 matching lines @@
                                (bmi_.bmiHeader.biBitCount >> 3);
   image_.reset(new uint8_t[bmi_.bmiHeader.biSizeImage]);
 }
 
 void MainWnd::VideoRenderer::OnFrame(
     const webrtc::VideoFrame& video_frame) {
 
   {
     AutoLock<VideoRenderer> lock(this);
 
-    rtc::scoped_refptr<webrtc::VideoFrameBuffer> buffer(
-        video_frame.video_frame_buffer());
+    rtc::scoped_refptr<webrtc::I420BufferInterface> buffer(
+        video_frame.video_frame_buffer()->ToI420());
     if (video_frame.rotation() != webrtc::kVideoRotation_0) {
       buffer = webrtc::I420Buffer::Rotate(*buffer, video_frame.rotation());
     }
 
     SetSize(buffer->width(), buffer->height());
 
     RTC_DCHECK(image_.get() != NULL);
     libyuv::I420ToARGB(buffer->DataY(), buffer->StrideY(),
                        buffer->DataU(), buffer->StrideU(),
                        buffer->DataV(), buffer->StrideV(),
                        image_.get(),
                        bmi_.bmiHeader.biWidth *
                            bmi_.bmiHeader.biBitCount / 8,
                        buffer->width(), buffer->height());
   }
   InvalidateRect(wnd_, NULL, TRUE);
 }