Handle Alpha channel in Canvas capture

media/base/video_util.h

Index: media/base/video_util.h
diff --git a/media/base/video_util.h b/media/base/video_util.h
index e51343344a098376193636406d5652dcece7d0dc..a67d0a4c96c410554cf44e3bd88fe78d9d628b1c 100644
--- a/media/base/video_util.h
+++ b/media/base/video_util.h
@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 
+#include "base/memory/ref_counted.h"
 #include "media/base/media_export.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
@@ -92,6 +93,10 @@ MEDIA_EXPORT void CopyRGBToVideoFrame(const uint8_t* source,
                                       const gfx::Rect& region_in_frame,
                                       VideoFrame* frame);
 
+// Converts a frame with YV12A format into I420 by dropping alpha channel.
+MEDIA_EXPORT scoped_refptr<VideoFrame> DropYV12AAlphaChannel(

[mcasas, 2016/02/29 23:48:01]

I was surprised that it returned a scoped_refptr<VideoFrame>
when the name seems to imply that it drops the A channel of
the passed frame. Please update name and comment to 
reflect that it wraps a given frame into a non-alpha frame.
Hmmm what about AsOpaque() ... ?

[emircan, 2016/03/01 20:07:55]

I see your point. WrapAsOpaque() might also imply RGBA->RGB. I will go with
WrapAsI420VideoFrame(). WDYT?

+    const scoped_refptr<VideoFrame>& frame);
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_UTIL_H_