Use SkSrc_Mode in SkCanvasVideoRenderer, to prevent transparent video frames from blending with reu…

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 5788015dabfbd2816913d582bdcd2498a8b8876c..702e620dc755c96c5bd7ec0dfa44883696ef89c9 100644
--- a/media/base/video_util.h
+++ b/media/base/video_util.h
@@ -44,6 +44,13 @@ MEDIA_EXPORT void CopyPlane(size_t plane, const uint8* source, int stride,
 // Fills |frame| containing YUV data to the given color values.
 MEDIA_EXPORT void FillYUV(VideoFrame* frame, uint8 y, uint8 u, uint8 v);
 
+// Fills |frame| containing YUVA data with the given color values.
+MEDIA_EXPORT void FillYUVA(VideoFrame* frame,
+                           uint8 y,
+                           uint8 u,
+                           uint8 v,
+                           uint8 a);
+
 // Creates a border in |frame| such that all pixels outside of
 // |view_area| are black. The size and position of |view_area|
 // must be even to align correctly with the color planes.