Change audio render thread checking to use new AudioRendererSink::BelongsToRendererThread()

media/audio/audio_device_thread.h

Index: media/audio/audio_device_thread.h
diff --git a/media/audio/audio_device_thread.h b/media/audio/audio_device_thread.h
index 61e5e8724ddc24b289c01c364e3491b137779462..a1c9d89d5b5422b05e8bf4a769537962be7850eb 100644
--- a/media/audio/audio_device_thread.h
+++ b/media/audio/audio_device_thread.h
@@ -97,6 +97,9 @@ class MEDIA_EXPORT AudioDeviceThread {
   // Returns true if the thread is stopped or stopping.
   bool IsStopped();
 
+  // Returns true if called on the device thread, otherwise false.
+  bool BelongsToRenderingThread();
+
  private:
   // Our own private SimpleThread override.  We implement this in a
   // private class so that we get the following benefits: