Remove dangling PlayingState pointers in WebRtcAudioRenderer.

content/renderer/media/webrtc_audio_renderer.h

Index: content/renderer/media/webrtc_audio_renderer.h
diff --git a/content/renderer/media/webrtc_audio_renderer.h b/content/renderer/media/webrtc_audio_renderer.h
index 1da6863cb2062447c10119f94712a229b24c9e70..4f6508edbcda8313c81d91f28ca19528928f02d9 100644
--- a/content/renderer/media/webrtc_audio_renderer.h
+++ b/content/renderer/media/webrtc_audio_renderer.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include <map>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -191,7 +192,8 @@ class CONTENT_EXPORT WebRtcAudioRenderer
   // sources associated with the |media_stream| based on the collective volume
   // of playing renderers.
   void OnPlayStateChanged(const blink::WebMediaStream& media_stream,
-                          PlayingState* state);
+                          PlayingState* state,
+                          bool playing_state_deleted);
 
   // Updates |sink_params_| and |audio_fifo_| based on |sink_|, and initializes
   // |sink_|.