New flag is_screencast in VideoOptions.

webrtc/api/videosource.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 341 matching lines @@
     return;
   }
 
   cricket::VideoOptions options;
   if (!ExtractVideoOptions(constraints, &options)) {
     LOG(LS_WARNING) << "Could not satisfy mandatory options.";
     SetState(kEnded);
     return;
   }
   options_.SetAll(options);
+  options_.is_screencast = rtc::Optional<bool>(video_capturer_->IsScreencast());
 
   format_ = GetBestCaptureFormat(formats);
   // Start the camera with our best guess.
   // TODO(perkj): Should we try again with another format it it turns out that
   // the camera doesn't produce frames with the correct format? Or will
   // cricket::VideCapturer be able to re-scale / crop to the requested
   // resolution?
   if (!channel_manager_->StartVideoCapture(video_capturer_.get(), format_)) {
     SetState(kEnded);
     return;
@@ skipping 40 matching lines @@
 void VideoSource::SetState(SourceState new_state) {
   // TODO(hbos): Temporarily disabled VERIFY due to webrtc:4776.
   // if (VERIFY(state_ != new_state)) {
   if (state_ != new_state) {
     state_ = new_state;
     FireOnChanged();
   }
 }
 
 }  // namespace webrtc