Fix getUserMedia so that failure is reported for invalid audio sources.

chrome/renderer/media/cast_receiver_session_delegate.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 "chrome/renderer/media/cast_receiver_session_delegate.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 30 matching lines @@
 }
 
 void CastReceiverSessionDelegate::ReceivePacket(
     std::unique_ptr<media::cast::Packet> packet) {
   cast_receiver_->ReceivePacket(std::move(packet));
 }
 
 void CastReceiverSessionDelegate::StartAudio(
     scoped_refptr<CastReceiverAudioValve> audio_valve) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
-  audio_valve_ = audio_valve;
+  audio_valve_ = std::move(audio_valve);
+  audio_valve_->OnStarted();
   cast_receiver_->RequestDecodedAudioFrame(on_audio_decoded_cb_);
 }
 
 void CastReceiverSessionDelegate::OnDecodedAudioFrame(
     std::unique_ptr<media::AudioBus> audio_bus,
     const base::TimeTicks& playout_time,
     bool is_continous) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   if (!audio_valve_)
     return;
@@ skipping 22 matching lines @@
 
 void CastReceiverSessionDelegate::OnDecodedVideoFrame(
     const scoped_refptr<media::VideoFrame>& video_frame,
     const base::TimeTicks& playout_time,
     bool is_continous) {
   if (frame_callback_.is_null())
     return;
   frame_callback_.Run(video_frame, playout_time);
   cast_receiver_->RequestDecodedVideoFrame(on_video_decoded_cb_);
 }