base::RefCounted now DCHECKs when referenced from multiple threads.

gpu/command_buffer/service/mailbox_manager.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 GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_
 
 #include "base/memory/ref_counted.h"
 #include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/gpu_export.h"
 
 namespace gpu {
 namespace gles2 {
 
 class Texture;
 
 // Manages resources scoped beyond the context or context group level.
-class GPU_EXPORT MailboxManager : public base::RefCounted<MailboxManager> {
+// TODO(mgiuca): Avoid using UnsafeRefCounted. http://crbug.com/469952.
+class GPU_EXPORT MailboxManager
+    : public base::UnsafeRefCounted<MailboxManager> {
  public:
   // Look up the texture definition from the named mailbox.
   virtual Texture* ConsumeTexture(const Mailbox& mailbox) = 0;
 
   // Put the texture into the named mailbox.
   virtual void ProduceTexture(const Mailbox& mailbox, Texture* texture) = 0;
 
   // If |true| then Pull/PushTextureUpdates() needs to be called.
   virtual bool UsesSync() = 0;
 
   // Used to synchronize texture state across share groups.
   virtual void PushTextureUpdates(uint32 sync_point) = 0;
   virtual void PullTextureUpdates(uint32 sync_point) = 0;
 
   // Destroy any mailbox that reference the given texture.
   virtual void TextureDeleted(Texture* texture) = 0;
 
  protected:
   MailboxManager() {}
   virtual ~MailboxManager() {}
 
  private:
-  friend class base::RefCounted<MailboxManager>;
+  friend class base::UnsafeRefCounted<MailboxManager>;
 
   DISALLOW_COPY_AND_ASSIGN(MailboxManager);
 };
 
 }  // namespage gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_