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

gpu/command_buffer/common/value_state.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_COMMON_VALUE_STATE_H_
 #define GPU_COMMAND_BUFFER_COMMON_VALUE_STATE_H_
 
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "gpu/gpu_export.h"
 
 namespace gpu {
 
 // Used to maintain Valuebuffer state, exposed to browser to
 // support passing ValueStates via IPC.
 union GPU_EXPORT ValueState {
   float float_value[4];
   int int_value[4];
 };
 
 // Refcounted wrapper for a hash_map of subscription targets to ValueStates
-class GPU_EXPORT ValueStateMap : public base::RefCounted<ValueStateMap> {
+// TODO(mgiuca): Avoid using UnsafeRefCounted. http://crbug.com/469952.
+class GPU_EXPORT ValueStateMap : public base::UnsafeRefCounted<ValueStateMap> {
  public:
   ValueStateMap();
 
   // Returns NULL if there is not ValueState for the target
   const ValueState* GetState(unsigned int target) const;
 
   void UpdateState(unsigned int target, const ValueState& state);
 
  protected:
   virtual ~ValueStateMap();
 
  private:
-  friend class base::RefCounted<ValueStateMap>;
+  friend class base::UnsafeRefCounted<ValueStateMap>;
 
   typedef base::hash_map<unsigned int, ValueState> Map;
 
   Map state_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ValueStateMap);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_VALUE_STATE_H_