WeakPtr destruction order cleanup: media edition.

content/browser/media/capture/web_contents_video_capture_device.cc

 // Copyright (c) 2012 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.
 //
 // Implementation notes: This needs to work on a variety of hardware
 // configurations where the speed of the CPU and GPU greatly affect overall
 // performance. Spanning several threads, the process of capturing has been
 // split up into four conceptual stages:
 //
 //   1. Reserve Buffer: Before a frame can be captured, a slot in the client's
@@ skipping 291 matching lines @@
   // otherwise.
   int fullscreen_widget_id_;
 
   // Last known RenderView size.
   gfx::Size last_view_size_;
 
   // Responsible for forwarding events from the active RenderWidgetHost to the
   // oracle, and initiating captures accordingly.
   scoped_ptr<ContentCaptureSubscription> subscription_;
 
-  // Weak pointer factory used to invalidate callbacks.
+  // Weak pointer factory used to invalidate callbacks.  NOTE: This must always
+  // be last so it's invalidated before other member variables might be
+  // accessed.
   base::WeakPtrFactory<WebContentsCaptureMachine> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsCaptureMachine);
 };
 
 // Responsible for logging the effective frame rate.
 // TODO(nick): Make this compatible with the push model and hook it back up.
 class VideoFrameDeliveryLog {
  public:
   VideoFrameDeliveryLog();
@@ skipping 495 matching lines @@
     scoped_ptr<Client> client) {
   DVLOG(1) << "Allocating " << params.requested_format.frame_size.ToString();
   core_->AllocateAndStart(params, client.Pass());
 }
 
 void WebContentsVideoCaptureDevice::StopAndDeAllocate() {
   core_->StopAndDeAllocate();
 }
 
 }  // namespace content