Replace MessageLoopProxy with SingleThreadTaskRunner for the rest of media/.

chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h

Index: chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h
diff --git a/chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h b/chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h
index 3f530563af1935b967be6404bfb98be838f1dd29..20f487f570d2f41d20e59db2b2f23502447f800f 100644
--- a/chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h
+++ b/chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_api.h
@@ -16,7 +16,7 @@
 #include "url/gurl.h"
 
 namespace base {
-class MessageLoopProxy;
+class SingleThreadTaskRunner;
 }
 
 namespace extensions {
@@ -107,8 +107,8 @@ class WebrtcAudioPrivateSetActiveSinkFunction
   void SwitchDone();
   void DoneOnUIThread();
 
-  // Message loop of the thread this class is constructed on.
-  const scoped_refptr<base::MessageLoopProxy> message_loop_;
+  // Task runner of the thread this class is constructed on.
+  const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   int tab_id_;
   std::string sink_id_;