Add mojo interface+impl for audio stream control.

content/browser/renderer_host/media/audio_renderer_host.cc

Index: content/browser/renderer_host/media/audio_renderer_host.cc
diff --git a/content/browser/renderer_host/media/audio_renderer_host.cc b/content/browser/renderer_host/media/audio_renderer_host.cc
index 6a99670a793ba144b237cd33b5fbc907f79cf519..6d630d6b64a55f1131c8ad7337d86612a0e8a7a6 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.cc
+++ b/content/browser/renderer_host/media/audio_renderer_host.cc
@@ -310,7 +310,7 @@ void AudioRendererHost::OnCreateStream(int stream_id,
   media_internals->SetWebContentsTitleForAudioLogEntry(
       stream_id, render_process_id_, render_frame_id, audio_log.get());
   delegates_.push_back(
-      base::WrapUnique<AudioOutputDelegate>(new AudioOutputDelegateImpl(
+      base::WrapUnique<media::AudioOutputDelegate>(new AudioOutputDelegateImpl(
           this, audio_manager_, std::move(audio_log), mirroring_manager_,
           media_observer, stream_id, render_frame_id, render_process_id_,
           params, device_unique_id)));
@@ -319,7 +319,7 @@ void AudioRendererHost::OnCreateStream(int stream_id,
 void AudioRendererHost::OnPlayStream(int stream_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  AudioOutputDelegate* delegate = LookupById(stream_id);
+  media::AudioOutputDelegate* delegate = LookupById(stream_id);
   if (!delegate) {
     SendErrorMessage(stream_id);
     return;
@@ -331,7 +331,7 @@ void AudioRendererHost::OnPlayStream(int stream_id) {
 void AudioRendererHost::OnPauseStream(int stream_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  AudioOutputDelegate* delegate = LookupById(stream_id);
+  media::AudioOutputDelegate* delegate = LookupById(stream_id);
   if (!delegate) {
     SendErrorMessage(stream_id);
     return;
@@ -343,7 +343,7 @@ void AudioRendererHost::OnPauseStream(int stream_id) {
 void AudioRendererHost::OnSetVolume(int stream_id, double volume) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  AudioOutputDelegate* delegate = LookupById(stream_id);
+  media::AudioOutputDelegate* delegate = LookupById(stream_id);
   if (!delegate) {
     SendErrorMessage(stream_id);
     return;
@@ -380,12 +380,12 @@ AudioRendererHost::LookupIteratorById(int stream_id) {
 
   return std::find_if(
       delegates_.begin(), delegates_.end(),
-      [stream_id](const std::unique_ptr<AudioOutputDelegate>& d) {
+      [stream_id](const std::unique_ptr<media::AudioOutputDelegate>& d) {
         return d->GetStreamId() == stream_id;
       });
 }
 
-AudioOutputDelegate* AudioRendererHost::LookupById(int stream_id) {
+media::AudioOutputDelegate* AudioRendererHost::LookupById(int stream_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   auto i = LookupIteratorById(stream_id);