Revert of media/vpx: Add support for VP9 alpha channel

media/base/video_frame.h

Index: media/base/video_frame.h
diff --git a/media/base/video_frame.h b/media/base/video_frame.h
index c9052f9d2e219e33690d37fecce8cf0091bd710d..edd9dd5559b5c0bb0ceed9f414cd1a5b6ec6bc1c 100644
--- a/media/base/video_frame.h
+++ b/media/base/video_frame.h
@@ -203,23 +203,6 @@
       const gfx::GpuMemoryBufferHandle& y_handle,
       const gfx::GpuMemoryBufferHandle& u_handle,
       const gfx::GpuMemoryBufferHandle& v_handle,
-      base::TimeDelta timestamp);
-
-  // Wraps external YUVA data of the given parameters with a VideoFrame.
-  // The returned VideoFrame does not own the data passed in.
-  static scoped_refptr<VideoFrame> WrapExternalYuvaData(
-      VideoPixelFormat format,
-      const gfx::Size& coded_size,
-      const gfx::Rect& visible_rect,
-      const gfx::Size& natural_size,
-      int32_t y_stride,
-      int32_t u_stride,
-      int32_t v_stride,
-      int32_t a_stride,
-      uint8_t* y_data,
-      uint8_t* u_data,
-      uint8_t* v_data,
-      uint8_t* a_data,
       base::TimeDelta timestamp);
 
 #if defined(OS_LINUX)