Implement MediaStreamTrack contentHint skeleton.

content/renderer/media/media_stream_audio_track.cc

 // Copyright 2014 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_stream_audio_track.h"
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "content/public/renderer/media_stream_audio_sink.h"
 #include "media/base/audio_bus.h"
@@ skipping 60 matching lines @@
       !!base::subtle::NoBarrier_AtomicExchange(&is_enabled_, enabled ? 1 : 0);
   if (enabled == previously_enabled)
     return;
 
   std::vector<MediaStreamAudioSink*> sinks_to_notify;
   deliverer_.GetConsumerList(&sinks_to_notify);
   for (MediaStreamAudioSink* sink : sinks_to_notify)
     sink->OnEnabledChanged(enabled);
 }
 
+void MediaStreamAudioTrack::SetContentHint(
+    blink::WebMediaStreamTrack::ContentHintType content_hint) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  std::vector<MediaStreamAudioSink*> sinks_to_notify;
+  deliverer_.GetConsumerList(&sinks_to_notify);
+  for (MediaStreamAudioSink* sink : sinks_to_notify)
+    sink->OnContentHintChanged(content_hint);
+}
+
 void* MediaStreamAudioTrack::GetClassIdentifier() const {
   return nullptr;
 }
 
 void MediaStreamAudioTrack::Start(const base::Closure& stop_callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!stop_callback.is_null());
   DCHECK(stop_callback_.is_null());
   DVLOG(1) << "Starting MediaStreamAudioTrack@" << this << '.';
   stop_callback_ = stop_callback;
@@ skipping 40 matching lines @@
   }
 }
 
 void MediaStreamAudioTrack::getSettings(
     blink::WebMediaStreamTrack::Settings& settings) {
   // TODO(hta): Extract the real value.
   settings.deviceId = blink::WebString("audio device ID");
 }
 
 }  // namespace content