Support (E)AC3 passthrough

media/renderers/audio_renderer_impl.h

Index: media/renderers/audio_renderer_impl.h
diff --git a/media/renderers/audio_renderer_impl.h b/media/renderers/audio_renderer_impl.h
index e4d6e94dfa0758c2e673ecae80538fd21fc0f6a8..b4237a12fb1f68b0ac4fc33dc8d1c954d7d09045 100644
--- a/media/renderers/audio_renderer_impl.h
+++ b/media/renderers/audio_renderer_impl.h
@@ -308,6 +308,12 @@ class MEDIA_EXPORT AudioRendererImpl
   // suspend/is suspended and when it resumes.
   bool is_suspending_;
 
+  // Whether to pass compressed audio bitstream to audio sink directly.
+  bool is_passthrough_;
+
+  // Track the last reported media time.
+  base::TimeDelta last_reported_media_time_;
+
   // End variables which must be accessed under |lock_|. ----------------------
 
   // NOTE: Weak pointers must be invalidated before all other member variables.