Change a disabled MediaStreamVideoTrack to output black video frames for each incoming frame.

content/renderer/media/rtc_video_renderer.cc

 // Copyright (c) 2012 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/rtc_video_renderer.h"
 
 #include "base/debug/trace_event.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/video_frame.h"
@@ skipping 63 matching lines @@
   }
 }
 
 void RTCVideoRenderer::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (state == blink::WebMediaStreamSource::ReadyStateEnded)
     RenderSignalingFrame();
 }
 
-void RTCVideoRenderer::OnEnabledChanged(bool enabled) {
-  DCHECK(message_loop_proxy_->BelongsToCurrentThread());
-  if (!enabled)
-    RenderSignalingFrame();
-}
-
 void RTCVideoRenderer::OnVideoFrame(
     const scoped_refptr<media::VideoFrame>& frame,
     const media::VideoCaptureFormat& format,
     const base::TimeTicks& estimated_capture_time) {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (state_ != STARTED) {
     return;
   }
 
   frame_size_ = frame->natural_size();
 
   TRACE_EVENT_INSTANT1("rtc_video_renderer",
                        "OnVideoFrame",
                        TRACE_EVENT_SCOPE_THREAD,
                        "timestamp",
                        frame->timestamp().InMilliseconds());
   repaint_cb_.Run(frame);
 }
 
 void RTCVideoRenderer::RenderSignalingFrame() {
   // This is necessary to make sure audio can play if the video tag src is
-  // a MediaStream video track that has been rejected, ended or disabled.
+  // a MediaStream video track that has been rejected or ended.
   // It also ensure that the renderer don't hold a reference to a real video
   // frame if no more frames are provided. This is since there might be a
   // finite number of available buffers. E.g, video that
   // originates from a video camera.
   scoped_refptr<media::VideoFrame> video_frame =
       media::VideoFrame::CreateBlackFrame(frame_size_);
   OnVideoFrame(video_frame, media::VideoCaptureFormat(), base::TimeTicks());
 }
 
 }  // namespace content