WeakPtr destruction order cleanup: media edition.

content/renderer/media/cdm_session_adapter.h

 // Copyright 2014 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_CDM_SESSION_ADAPTER_H_
 #define CONTENT_RENDERER_MEDIA_CDM_SESSION_ADAPTER_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 69 matching lines @@
   void OnSessionClosed(uint32 session_id);
   void OnSessionError(uint32 session_id,
                       media::MediaKeys::KeyError error_code,
                       uint32 system_code);
 
   // Helper function of the callbacks.
   WebContentDecryptionModuleSessionImpl* GetSession(uint32 session_id);
 
   scoped_ptr<media::MediaKeys> media_keys_;
 
-  base::WeakPtrFactory<CdmSessionAdapter> weak_ptr_factory_;
-
   SessionMap sessions_;
 
   // Session ID should be unique per renderer process for debugging purposes.
   static uint32 next_session_id_;
 
+  // NOTE: This must always be last so it's invalidated before other member
+  // variables might be accessed.
+  base::WeakPtrFactory<CdmSessionAdapter> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(CdmSessionAdapter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_CDM_SESSION_ADAPTER_H_