2D Canvas doesn't blend video with the destination buffer.

media/filters/skcanvas_video_renderer.cc

Index: media/filters/skcanvas_video_renderer.cc
diff --git a/media/filters/skcanvas_video_renderer.cc b/media/filters/skcanvas_video_renderer.cc
index 062e317b71da03476438e156bb2f5d2cedc47b00..46bb7e6b453c3d102bd7a49eb55aa468c1d74dfb 100644
--- a/media/filters/skcanvas_video_renderer.cc
+++ b/media/filters/skcanvas_video_renderer.cc
@@ -188,7 +188,8 @@ SkCanvasVideoRenderer::~SkCanvasVideoRenderer() {}
 void SkCanvasVideoRenderer::Paint(media::VideoFrame* video_frame,
                                   SkCanvas* canvas,
                                   const gfx::RectF& dest_rect,
-                                  uint8 alpha) {
+                                  uint8 alpha,
+                                  SkXfermode::Mode mode) {
   if (alpha == 0) {
     return;
   }
@@ -213,9 +214,7 @@ void SkCanvasVideoRenderer::Paint(media::VideoFrame* video_frame,
     last_frame_timestamp_ = video_frame->timestamp();
   }
 
-  // Use SRC mode so we completely overwrite the buffer (in case we have alpha)
-  // this means we don't need the extra cost of clearing the buffer first.
-  paint.setXfermode(SkXfermode::Create(SkXfermode::kSrc_Mode));
+  paint.setXfermodeMode(mode);
 
   // Paint using |last_frame_|.
   paint.setFilterLevel(SkPaint::kLow_FilterLevel);