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

content/renderer/media/webmediaplayer_impl.cc

Index: content/renderer/media/webmediaplayer_impl.cc
diff --git a/content/renderer/media/webmediaplayer_impl.cc b/content/renderer/media/webmediaplayer_impl.cc
index 09633bde08c4e972a6b4742d67ba4a5bf90ac9bd..38db09c273f81b33b293a72398cd5e204566069a 100644
--- a/content/renderer/media/webmediaplayer_impl.cc
+++ b/content/renderer/media/webmediaplayer_impl.cc
@@ -532,9 +532,16 @@ bool WebMediaPlayerImpl::didLoadingProgress() {
   return pipeline_progress || data_progress;
 }
 
-void WebMediaPlayerImpl::paint(WebCanvas* canvas,
-                               const WebRect& rect,
+void WebMediaPlayerImpl::paint(blink::WebCanvas* canvas,
+                               const blink::WebRect& rect,
                                unsigned char alpha) {
+  paint(canvas, rect, alpha, SkXfermode::kSrcOver_Mode);
+}
+
+void WebMediaPlayerImpl::paint(blink::WebCanvas* canvas,
+                               const blink::WebRect& rect,
+                               unsigned char alpha,
+                               SkXfermode::Mode mode) {
   DCHECK(main_loop_->BelongsToCurrentThread());
   TRACE_EVENT0("media", "WebMediaPlayerImpl:paint");
 
@@ -547,7 +554,8 @@ void WebMediaPlayerImpl::paint(WebCanvas* canvas,
       GetCurrentFrameFromCompositor();
 
   gfx::Rect gfx_rect(rect);
-  skcanvas_video_renderer_.Paint(video_frame.get(), canvas, gfx_rect, alpha);
+  skcanvas_video_renderer_.Paint(
+      video_frame.get(), canvas, gfx_rect, alpha, mode);
 }
 
 bool WebMediaPlayerImpl::hasSingleSecurityOrigin() const {