WeakPtr destruction order cleanup: media edition.

content/renderer/media/webaudiosourceprovider_impl.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_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
@@ skipping 38 matching lines @@
   virtual void Initialize(const media::AudioParameters& params,
                           RenderCallback* renderer) OVERRIDE;
 
  protected:
   virtual ~WebAudioSourceProviderImpl();
 
  private:
   // Calls setFormat() on |client_| from the Blink renderer thread.
   void OnSetFormat();
 
-  base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_this_;
-
   // Closure that posts a task to call OnSetFormat() on the renderer thread.
   base::Closure set_format_cb_;
 
   // Set to true when Initialize() is called.
   int channels_;
   int sample_rate_;
   double volume_;
 
   // Tracks the current playback state.
   enum PlaybackState { kStopped, kStarted, kPlaying };
   PlaybackState state_;
 
   // Where audio comes from.
   media::AudioRendererSink::RenderCallback* renderer_;
 
   // When set via setClient() it overrides |sink_| for consuming audio.
   blink::WebAudioSourceProviderClient* client_;
 
   // Where audio ends up unless overridden by |client_|.
   base::Lock sink_lock_;
   scoped_refptr<media::AudioRendererSink> sink_;
   scoped_ptr<media::AudioBus> bus_wrapper_;
 
+  // NOTE: This must always be last so it's invalidated before other member
+  // variables might be accessed.
+  base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_this_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_