Implement AudioRendererMixerInput::CurrentThreadIsRenderingThread().

media/base/audio_renderer_mixer.cc

Index: media/base/audio_renderer_mixer.cc
diff --git a/media/base/audio_renderer_mixer.cc b/media/base/audio_renderer_mixer.cc
index e4c1e8005cdf30220bf156de29b4148a1c35a0ac..008fcce793320af352ff80ab17ff51c8ea17cff3 100644
--- a/media/base/audio_renderer_mixer.cc
+++ b/media/base/audio_renderer_mixer.cc
@@ -118,6 +118,10 @@ OutputDeviceInfo AudioRendererMixer::GetOutputDeviceInfo() {
   return audio_sink_->GetOutputDeviceInfo();
 }
 
+bool AudioRendererMixer::CurrentThreadIsRenderingThread() {
+  return audio_sink_->CurrentThreadIsRenderingThread();
+}
+
 int AudioRendererMixer::Render(AudioBus* audio_bus,
                                uint32_t frames_delayed,
                                uint32_t frames_skipped) {