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 429 matching lines @@
           ->GetGLInterface();
   media::SkCanvasVideoRenderer::CopyVideoFrameSingleTextureToGLTexture(
       gl, video_frame.get(), texture, internal_format, type, premultiply_alpha,
       flip_y);
   return true;
 }
 
 void WebMediaPlayerMS::OnFrameAvailable(
     const scoped_refptr<media::VideoFrame>& frame) {
   DVLOG(3) << __FUNCTION__;
   DCHECK(thread_checker_.CalledOnValidThread());

[mcasas, 2016/02/25 22:06:25]

nit: DCHECK(I420 or YV12A) ?

[emircan, 2016/02/26 01:33:08]

I don't think it is necessary. VideoResourceUpdater::CreateForSoftwarePlanes
shows that we support many other formats, so it wouldn't hurt to send them down
the line as well.

[0]
https://code.google.com/p/chromium/codesearch#chromium/src/cc/resources/video...

 
   if (render_frame_suspended_)
     return;
 
   base::TimeTicks render_time;
   if (frame->metadata()->GetTimeTicks(media::VideoFrameMetadata::REFERENCE_TIME,
                                       &render_time)) {
     TRACE_EVENT1("webrtc", "WebMediaPlayerMS::OnFrameAvailable",
                  "Ideal Render Instant", render_time.ToInternalValue());
   } else {
     TRACE_EVENT0("webrtc", "WebMediaPlayerMS::OnFrameAvailable");
   }
 
   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);

[mcasas, 2016/02/25 22:06:25]

SetContentsOpaque(frame->format() != media::PIXEL_FORMAT_YV12A) ?

[emircan, 2016/02/26 01:33:08]

This value is set once. Since we started switching between YV12A and I420 after
the last changes, we can no longer depend on first frame representing the whole.

       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