Reland of Move MutableDataY{,U,V} methods to I420Buffer only.

webrtc/modules/video_coding/codecs/i420/i420.cc

Index: webrtc/modules/video_coding/codecs/i420/i420.cc
diff --git a/webrtc/modules/video_coding/codecs/i420/i420.cc b/webrtc/modules/video_coding/codecs/i420/i420.cc
index 93204dde9ce72f1e04032757def1dae5f902d8a8..d0c8d0c62c97113090ee35aea284a6098b4c4f58 100644
--- a/webrtc/modules/video_coding/codecs/i420/i420.cc
+++ b/webrtc/modules/video_coding/codecs/i420/i420.cc
@@ -137,8 +137,7 @@
 }
 
 I420Decoder::I420Decoder()
-    : _decodedImage(),
-      _width(0),
+    : _width(0),
       _height(0),
       _inited(false),
       _decodeCompleteCallback(NULL) {}
@@ -199,17 +198,19 @@
   }
   // Set decoded image parameters.
   int half_width = (_width + 1) / 2;
-  _decodedImage.CreateEmptyFrame(_width, _height, _width, half_width,
-                                 half_width);
-  // Converting from buffer to plane representation.
+  rtc::scoped_refptr<webrtc::I420Buffer> frame_buffer =
+      I420Buffer::Create(_width, _height, _width, half_width, half_width);
+
+  // Converting from raw buffer I420Buffer.
   int ret = ConvertToI420(kI420, buffer, 0, 0, _width, _height, 0,
-                          kVideoRotation_0, &_decodedImage);
+                          kVideoRotation_0, frame_buffer.get());
   if (ret < 0) {
     return WEBRTC_VIDEO_CODEC_MEMORY;
   }
-  _decodedImage.set_timestamp(inputImage._timeStamp);
-
-  _decodeCompleteCallback->Decoded(_decodedImage);
+
+  VideoFrame decoded_image(frame_buffer, inputImage._timeStamp, 0,
+                           webrtc::kVideoRotation_0);
+  _decodeCompleteCallback->Decoded(decoded_image);
   return WEBRTC_VIDEO_CODEC_OK;
 }