Remove base::SupportsWeakPtr from {Audio,Video}Sender

media/cast/sender/video_sender.h

Index: media/cast/sender/video_sender.h
diff --git a/media/cast/sender/video_sender.h b/media/cast/sender/video_sender.h
index 778ba0320e4d4bbdd3438667fe3793ddc24806b7..2af7e66670150f1a47845d2cd3f681bd78258caf 100644
--- a/media/cast/sender/video_sender.h
+++ b/media/cast/sender/video_sender.h
@@ -110,9 +110,6 @@ class VideoSender : public FrameSender,
   // to duplicately respond to multiple Pli messages in a short period.
   base::TimeTicks last_time_attempted_to_resolve_pli_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<VideoSender> weak_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(VideoSender);
 };