Handle ReadyStateEnded in MediaRecorderHandler

content/renderer/media/media_recorder_handler.cc

 // Copyright 2015 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_recorder_handler.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 159 matching lines @@
   const bool use_video_tracks =
       !video_tracks.isEmpty() && video_tracks[0].isEnabled() &&
       video_tracks[0].source().getReadyState() !=
           blink::WebMediaStreamSource::ReadyStateEnded;
   const bool use_audio_tracks =
       !audio_tracks.isEmpty() && MediaStreamAudioTrack::From(audio_tracks[0]) &&
       audio_tracks[0].isEnabled() &&
       audio_tracks[0].source().getReadyState() !=
           blink::WebMediaStreamSource::ReadyStateEnded;
 
+  if (!use_video_tracks && !use_audio_tracks) {
+    LOG(WARNING) << __FUNCTION__ << ": no tracks to be recorded.";
+    return false;
+  }
+
   webm_muxer_.reset(new media::WebmMuxer(
       CodecIdToMediaVideoCodec(codec_id_), use_video_tracks, use_audio_tracks,
       base::Bind(&MediaRecorderHandler::WriteData,
                  weak_factory_.GetWeakPtr())));
 
   if (use_video_tracks) {
     // TODO(mcasas): The muxer API supports only one video track. Extend it to
     // several video tracks, see http://crbug.com/528523.
     LOG_IF(WARNING, video_tracks.size() > 1u)
         << "Recording multiple video tracks is not implemented. "
@@ skipping 116 matching lines @@
     recorder->OnData(audio_bus, timestamp);
 }
 
 void MediaRecorderHandler::SetAudioFormatForTesting(
     const media::AudioParameters& params) {
   for (auto* recorder : audio_recorders_)
     recorder->OnSetFormat(params);
 }
 
 }  // namespace content