Handle Alpha channel in Canvas capture

content/renderer/media/webmediaplayer_ms.cc

 // 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.
 
 #include "content/renderer/media/webmediaplayer_ms.h"
 
 #include <stddef.h>
 #include <limits>
 #include <string>
 #include <utility>
@@ skipping 452 matching lines @@
 
   if (!received_first_frame_) {
     received_first_frame_ = true;
     SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
     SetReadyState(WebMediaPlayer::ReadyStateHaveEnoughData);
 
     if (video_frame_provider_.get()) {
       video_weblayer_.reset(new cc_blink::WebLayerImpl(
           cc::VideoLayer::Create(cc_blink::WebLayerImpl::LayerSettings(),
                                  compositor_.get(), media::VIDEO_ROTATION_0)));
-      video_weblayer_->layer()->SetContentsOpaque(true);
+      video_weblayer_->layer()->SetContentsOpaque(false);
       video_weblayer_->SetContentsOpaqueIsFixed(true);
       get_client()->setWebLayer(video_weblayer_.get());
     }
   }
 
   // As EnqueueFrame can potentially change |current_frame_|, we need to do
   // the size change check before it. Otherwise, we are running the risk of not
   // detecting a size change event.
   const bool size_changed =
       compositor_->GetCurrentSize() != frame->natural_size();
@@ skipping 32 matching lines @@
 media::SkCanvasVideoRenderer* WebMediaPlayerMS::GetSkCanvasVideoRenderer() {
   return &video_renderer_;
 }
 
 void WebMediaPlayerMS::ResetCanvasCache() {
   DCHECK(thread_checker_.CalledOnValidThread());
   video_renderer_.ResetCache();
 }
 
 }  // namespace content