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

content/renderer/media/android/webmediaplayer_android.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_
 #define CONTENT_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_
 
 #include <jni.h>
 #include <string>
 #include <vector>
@@ skipping 94 matching lines @@
   // Poster image, as defined in the <video> element.
   virtual void setPoster(const blink::WebURL& poster) OVERRIDE;
 
   // Methods for painting.
   // FIXME: This path "only works" on Android. It is a workaround for the
   // issue that Skia could not handle Android's GL_TEXTURE_EXTERNAL_OES texture
   // internally. It should be removed and replaced by the normal paint path.
   // https://code.google.com/p/skia/issues/detail?id=1189
   virtual void paint(blink::WebCanvas* canvas,
                      const blink::WebRect& rect,
+                     unsigned char alpha,
+                     SkXfermode::Mode mode);
+  // TODO(dshwang): remove it.
+  virtual void paint(blink::WebCanvas* canvas,
+                     const blink::WebRect& rect,
                      unsigned char alpha);
 
   virtual bool copyVideoTextureToPlatformTexture(
       blink::WebGraphicsContext3D* web_graphics_context,
       unsigned int texture,
       unsigned int level,
       unsigned int internal_format,
       unsigned int type,
       bool premultiply_alpha,
       bool flip_y);
@@ skipping 327 matching lines @@
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<WebMediaPlayerAndroid> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerAndroid);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_