WeakPtr destruction order cleanup: media edition.

content/renderer/media/rtc_video_encoder.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_
 #define CONTENT_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 81 matching lines @@
   // The RTCVideoEncoder::Impl that does all the work.
   scoped_refptr<Impl> impl_;
 
   // We cannot immediately return error conditions to the WebRTC user of this
   // class, as there is no error callback in the webrtc::VideoEncoder interface.
   // Instead, we cache an error status here and return it the next time an
   // interface entry point is called.
   int32_t impl_status_;
 
   // Weak pointer factory for posting back VEA::Client notifications to
-  // RTCVideoEncoder.
+  // RTCVideoEncoder.  NOTE: This must always be last so it's invalidated before
+  // other member variables might be accessed.
   base::WeakPtrFactory<RTCVideoEncoder> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCVideoEncoder);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_