Fixed the crash when the WebRtcAudioCapturer::|buffer_| is NULL

content/renderer/media/webrtc_local_audio_track.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/webrtc_local_audio_track.h"
 
 #include "content/renderer/media/webrtc_audio_capturer.h"
 #include "content/renderer/media/webrtc_audio_capturer_sink_owner.h"
 
 namespace content {
@@ skipping 12 matching lines @@
 
 WebRtcLocalAudioTrack::WebRtcLocalAudioTrack(
     const std::string& label,
     const scoped_refptr<WebRtcAudioCapturer>& capturer,
     webrtc::AudioSourceInterface* track_source)
     : webrtc::MediaStreamTrack<webrtc::AudioTrackInterface>(label),
       capturer_(capturer),
       track_source_(track_source) {
   DCHECK(capturer);
   capturer_->AddSink(this);
-  params_ = capturer_->audio_parameters();
   DVLOG(1) << "WebRtcLocalAudioTrack::WebRtcLocalAudioTrack()";
 }
 
 WebRtcLocalAudioTrack::~WebRtcLocalAudioTrack() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(sinks_.empty());
   capturer_->RemoveSink(this);
   DVLOG(1) << "WebRtcLocalAudioTrack::~WebRtcLocalAudioTrack()";
 }
 
@@ skipping 21 matching lines @@
        ++it) {
     (*it)->CaptureData(audio_data, number_of_channels, number_of_frames,
                        audio_delay_milliseconds, volume);
   }
 }
 
 void WebRtcLocalAudioTrack::SetCaptureFormat(
     const media::AudioParameters& params) {
   base::AutoLock auto_lock(lock_);
   params_ = params;
+  // Update all the existing sinks with the new format.

[henrika (OOO until Aug 14), 2013/05/07 09:13:27]

nit, new line above comment

[no longer working on chromium, 2013/05/07 09:21:48]

Done.

+  for (SinkList::const_iterator it = sinks_.begin();
+       it != sinks_.end(); ++it)
+    (*it)->SetCaptureFormat(params);
 }
 
 // webrtc::AudioTrackInterface implementation.
 webrtc::AudioSourceInterface* WebRtcLocalAudioTrack::GetSource() const {
   return track_source_;
 }
 
 std::string WebRtcLocalAudioTrack::kind() const {
   return kAudioTrackKind;
 }
@@ skipping 29 matching lines @@
   if (it != sinks_.end()) {
     // Clear the delegate to ensure that no more capture callbacks will
     // be sent to this sink. Also avoids a possible crash which can happen
     // if this method is called while capturing is active.
     (*it)->Reset();
     sinks_.erase(it);
   }
 }
 
 }  // namespace content