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

webrtc/common_video/video_frame.cc

Index: webrtc/common_video/video_frame.cc
diff --git a/webrtc/common_video/video_frame.cc b/webrtc/common_video/video_frame.cc
index 4b29be9d16b0b65a0302b92db32ffe3dcba2b92c..e00ca27b8a9a63e6d385f44a6febcc06312e9bd4 100644
--- a/webrtc/common_video/video_frame.cc
+++ b/webrtc/common_video/video_frame.cc
@@ -87,18 +87,10 @@
   const int expected_size_y = height * stride_y;
   const int expected_size_u = half_height * stride_u;
   const int expected_size_v = half_height * stride_v;
-  // Allocate a new buffer.
-  rtc::scoped_refptr<I420Buffer> buffer_ =
-      I420Buffer::Create(width, height, stride_y, stride_u, stride_v);
-
-  memcpy(buffer_->MutableDataY(), buffer_y, expected_size_y);
-  memcpy(buffer_->MutableDataU(), buffer_u, expected_size_u);
-  memcpy(buffer_->MutableDataV(), buffer_v, expected_size_v);
-
-  video_frame_buffer_ = buffer_;
-  timestamp_rtp_ = 0;
-  ntp_time_ms_ = 0;
-  timestamp_us_ = 0;
+  CreateEmptyFrame(width, height, stride_y, stride_u, stride_v);
+  memcpy(video_frame_buffer_->MutableDataY(), buffer_y, expected_size_y);
+  memcpy(video_frame_buffer_->MutableDataU(), buffer_u, expected_size_u);
+  memcpy(video_frame_buffer_->MutableDataV(), buffer_v, expected_size_v);
   rotation_ = rotation;
 }