WeakPtr destruction order cleanup: media edition.

media/cast/audio_sender/audio_sender.h

Index: media/cast/audio_sender/audio_sender.h
diff --git a/media/cast/audio_sender/audio_sender.h b/media/cast/audio_sender/audio_sender.h
index 6afa7cf9f4a80f14e8fdd7887cd96321ad1a60ab..d4742139e7ab0c51d5114257d266968f67996865 100644
--- a/media/cast/audio_sender/audio_sender.h
+++ b/media/cast/audio_sender/audio_sender.h
@@ -76,8 +76,6 @@ class AudioSender : public base::NonThreadSafe,
 
   void InitializeTimers();
 
-  base::WeakPtrFactory<AudioSender> weak_factory_;
-
   scoped_refptr<CastEnvironment> cast_environment_;
   transport::CastTransportSender* const transport_sender_;
   scoped_refptr<AudioEncoder> audio_encoder_;
@@ -87,6 +85,10 @@ class AudioSender : public base::NonThreadSafe,
   bool timers_initialized_;
   CastInitializationStatus cast_initialization_cb_;
 
+  // NOTE: This must always be last so it's invalidated before other member
+  // variables might be accessed.
+  base::WeakPtrFactory<AudioSender> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioSender);
 };