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..1ffefc5a29146738e7a3274a2e9b1ef70e0a583a 100644
--- a/media/audio/audio_device_thread.h
+++ b/media/audio/audio_device_thread.h
@@ -12,6 +12,7 @@
 #include "base/memory/shared_memory.h"
 #include "base/sync_socket.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/thread_checker.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/media_export.h"
 
@@ -68,6 +69,11 @@ class MEDIA_EXPORT AudioDeviceThread {
     const int total_segments_;
     int segment_length_;
 
+    // Detached in constructor and attached in InitializeOnAudioThread() which
+    // is called on the audio device thread. Sub-classes can then use it for
+    // various thread checking purposes.
+    base::ThreadChecker thread_checker_;
+
    private:
     DISALLOW_COPY_AND_ASSIGN(Callback);
   };