Handle Alpha channel in Canvas capture

media/base/video_frame.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_VIDEO_FRAME_H_
 #define MEDIA_BASE_VIDEO_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 226 matching lines @@
   // http://crbug.com/401308
   static scoped_refptr<VideoFrame> WrapCVPixelBuffer(
       CVPixelBufferRef cv_pixel_buffer,
       base::TimeDelta timestamp);
 #endif
 
   // Wraps |frame|. |visible_rect| must be a sub rect within
   // frame->visible_rect().
   static scoped_refptr<VideoFrame> WrapVideoFrame(
       const scoped_refptr<VideoFrame>& frame,
+      VideoPixelFormat format,
       const gfx::Rect& visible_rect,
       const gfx::Size& natural_size);
 
   // Creates a frame which indicates end-of-stream.
   static scoped_refptr<VideoFrame> CreateEOSFrame();
 
   // Allocates YV12 frame based on |size|, and sets its data to the YUV(y,u,v).
   static scoped_refptr<VideoFrame> CreateColorFrame(const gfx::Size& size,
                                                     uint8_t y,
                                                     uint8_t u,
@@ skipping 268 matching lines @@
   gpu::SyncToken release_sync_token_;
 
   VideoFrameMetadata metadata_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_