Handle Alpha channel in Canvas capture

content/renderer/media/media_stream_video_track.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/media_stream_video_track.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 157 matching lines @@
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   if (!black_frame_.get() ||
       black_frame_->natural_size() != reference_frame->natural_size()) {
     black_frame_ =
         media::VideoFrame::CreateBlackFrame(reference_frame->natural_size());
   }
 
   // Wrap |black_frame_| so we get a fresh timestamp we can modify. Frames
   // returned from this function may still be in use.
   scoped_refptr<media::VideoFrame> wrapped_black_frame =
-      media::VideoFrame::WrapVideoFrame(
-          black_frame_, black_frame_->visible_rect(),
-          black_frame_->natural_size());
+      media::VideoFrame::WrapVideoFrame(black_frame_, black_frame_->format(),
+                                        black_frame_->visible_rect(),
+                                        black_frame_->natural_size());
   if (!wrapped_black_frame)
     return nullptr;
   wrapped_black_frame->AddDestructionObserver(
       base::Bind(&ReleaseOriginalFrame, black_frame_));
 
   wrapped_black_frame->set_timestamp(reference_frame->timestamp());
   base::TimeTicks reference_time;
   if (reference_frame->metadata()->GetTimeTicks(
           media::VideoFrameMetadata::REFERENCE_TIME, &reference_time)) {
     wrapped_black_frame->metadata()->SetTimeTicks(
@@ skipping 84 matching lines @@
 }
 
 void MediaStreamVideoTrack::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   for (auto* sink : sinks_)
     sink->OnReadyStateChanged(state);
 }
 
 }  // namespace content