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

webrtc/media/engine/webrtcvideoframe.cc

Index: webrtc/media/engine/webrtcvideoframe.cc
diff --git a/webrtc/media/engine/webrtcvideoframe.cc b/webrtc/media/engine/webrtcvideoframe.cc
index f35a45ac6c3a767f2d8b7a0c3c6cbeda5dfcdad5..7b5a68064f4277989cf339fac54554d2ad9350eb 100644
--- a/webrtc/media/engine/webrtcvideoframe.cc
+++ b/webrtc/media/engine/webrtcvideoframe.cc
@@ -129,7 +129,9 @@
     new_height = dw;
   }
 
-  InitToEmptyBuffer(new_width, new_height);
+  rtc::scoped_refptr<webrtc::I420Buffer> buffer =
+      webrtc::I420Buffer::Create(new_width, new_height);
+  video_frame_buffer_ = buffer;
   rotation_ = apply_rotation ? webrtc::kVideoRotation_0 : rotation;
 
   int horiz_crop = ((w - dw) / 2) & ~1;
@@ -140,15 +142,10 @@
   int idh = (h < 0) ? -dh : dh;
   int r = libyuv::ConvertToI420(
       sample, sample_size,
-      video_frame_buffer_->MutableDataY(),
-      video_frame_buffer_->StrideY(),
-      video_frame_buffer_->MutableDataU(),
-      video_frame_buffer_->StrideU(),
-      video_frame_buffer_->MutableDataV(),
-      video_frame_buffer_->StrideV(),
-      horiz_crop, vert_crop,
-      w, h,
-      dw, idh,
+      buffer->MutableDataY(), buffer->StrideY(),
+      buffer->MutableDataU(), buffer->StrideU(),
+      buffer->MutableDataV(), buffer->StrideV(),
+      horiz_crop, vert_crop, w, h, dw, idh,
       static_cast<libyuv::RotationMode>(
           apply_rotation ? rotation : webrtc::kVideoRotation_0),
       format);
@@ -162,7 +159,7 @@
 }
 
 void WebRtcVideoFrame::InitToEmptyBuffer(int w, int h) {
-  video_frame_buffer_ = new rtc::RefCountedObject<webrtc::I420Buffer>(w, h);
+  video_frame_buffer_ = webrtc::I420Buffer::Create(w, h);
   rotation_ = webrtc::kVideoRotation_0;
 }