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

webrtc/modules/video_capture/video_capture_impl.h

Index: webrtc/modules/video_capture/video_capture_impl.h
diff --git a/webrtc/modules/video_capture/video_capture_impl.h b/webrtc/modules/video_capture/video_capture_impl.h
index e9fee7edb42cedc1237510c18e31aafef7db60f5..7d785c3a908cdb9213a1e76204e39fac145ab13f 100644
--- a/webrtc/modules/video_capture/video_capture_impl.h
+++ b/webrtc/modules/video_capture/video_capture_impl.h
@@ -137,6 +137,8 @@
     VideoRotation _rotateFrame;  // Set if the frame should be rotated by the
                                  // capture module.
 
+    VideoFrame _captureFrame;
+
     // Indicate whether rotation should be applied before delivered externally.
     bool apply_rotation_;
 };