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

gpu/command_buffer/service/valuebuffer_manager.h

 // Copyright (c) 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_VALUEBUFFER_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_VALUEBUFFER_MANAGER_H_
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "gpu/command_buffer/common/value_state.h"
 #include "gpu/gpu_export.h"
 
 namespace content {
 class GpuChannel;
 }
 
 namespace gpu {
 namespace gles2 {
 
 class ValuebufferManager;
 
+// TODO(mgiuca): Avoid using UnsafeRefCounted. http://crbug.com/469952.
 class GPU_EXPORT SubscriptionRefSet
-    : public base::RefCounted<SubscriptionRefSet> {
+    : public base::UnsafeRefCounted<SubscriptionRefSet> {
  public:
   class GPU_EXPORT Observer {
    public:
     virtual ~Observer();
 
     virtual void OnAddSubscription(unsigned int target) = 0;
     virtual void OnRemoveSubscription(unsigned int target) = 0;
   };
 
   SubscriptionRefSet();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
  protected:
   virtual ~SubscriptionRefSet();
 
  private:
-  friend class base::RefCounted<SubscriptionRefSet>;
+  friend class base::UnsafeRefCounted<SubscriptionRefSet>;
   friend class ValuebufferManager;
 
   typedef base::hash_map<unsigned int, int> RefSet;
 
   void AddSubscription(unsigned int target);
   void RemoveSubscription(unsigned int target);
 
   RefSet reference_set_;
 
   ObserverList<Observer, true> observers_;
@@ skipping 98 matching lines @@
   // many value buffers are currently subscribed to each
   scoped_refptr<SubscriptionRefSet> subscription_ref_set_;
 
   DISALLOW_COPY_AND_ASSIGN(ValuebufferManager);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_VALUEBUFFER_MANAGER_H_