Revert of New static method I420Buffer::SetToBlack.

webrtc/common_video/include/video_frame_buffer.h

Index: webrtc/common_video/include/video_frame_buffer.h
diff --git a/webrtc/common_video/include/video_frame_buffer.h b/webrtc/common_video/include/video_frame_buffer.h
index 890922f21be2dfa9896db25b5627ebc8be0b0c53..984bd50d674e78d7e7aedfc252fcfef8810b6963 100644
--- a/webrtc/common_video/include/video_frame_buffer.h
+++ b/webrtc/common_video/include/video_frame_buffer.h
@@ -87,17 +87,7 @@
  public:
   I420Buffer(int width, int height);
   I420Buffer(int width, int height, int stride_y, int stride_u, int stride_v);
-
-  // Sets all three planes to all zeros. Used to work around for
-  // quirks in memory checkers
-  // (https://bugs.chromium.org/p/libyuv/issues/detail?id=377) and
-  // ffmpeg (http://crbug.com/390941).
-  // TODO(nisse): Should be deleted if/when those issues are resolved
-  // in a better way.
   void InitializeData();
-
-  // Sets the frame buffer to all black.
-  void SetToBlack();
 
   int width() const override;
   int height() const override;