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

cc/resources/video_resource_updater.cc

Index: cc/resources/video_resource_updater.cc
diff --git a/cc/resources/video_resource_updater.cc b/cc/resources/video_resource_updater.cc
index a1286b917b4f2bde8af4248eb7654b2da202db4d..2beb5e8ddcbb9c2e1fa9a94da77e5ee6facd9b88 100644
--- a/cc/resources/video_resource_updater.cc
+++ b/cc/resources/video_resource_updater.cc
@@ -249,10 +249,14 @@ VideoFrameExternalResources VideoResourceUpdater::CreateForSoftwarePlanes(
     {
       ResourceProvider::ScopedWriteLockSoftware lock(
           resource_provider_, plane_resources[0].resource_id);
+      // Use SRC mode so we completely overwrite the buffer because reusing the

[danakj, 2014/08/06 18:07:16]

It's more like Use Src mode to avoid clearing the buffer first?

[dshwang, 2014/08/06 18:12:40]

Done.

+      // resource among frames.
+      lock.sk_canvas()->clear(SK_ColorTRANSPARENT);

[danakj, 2014/08/06 18:07:16]

Clear isn't needed then anymore right?

[dshwang, 2014/08/06 18:12:40]

Oops, you're right! Done.

       video_renderer_->Paint(video_frame.get(),
                              lock.sk_canvas(),
                              video_frame->visible_rect(),
-                             0xff);
+                             0xff,
+                             SkXfermode::kSrc_Mode);
     }
 
     RecycleResourceData recycle_data = {