Enable Oilpan for core/timing/.

Source/core/timing/ConsoleMemory.h

 // Copyright 2015 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 ConsoleMemory_h
 #define ConsoleMemory_h
 
 #include "platform/Supplementable.h"
 
 namespace blink {
 
 class Console;
 class MemoryInfo;
 
 class ConsoleMemory final : public NoBaseWillBeGarbageCollectedFinalized<ConsoleMemory>, public WillBeHeapSupplement<Console> {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(ConsoleMemory);
     DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(ConsoleMemory);
 public:
     static ConsoleMemory& from(Console&);
     static MemoryInfo* memory(Console&);
     static void setMemory(Console&, MemoryInfo*) { }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     static const char* supplementName() { return "ConsoleMemory"; }
     MemoryInfo* memory();
 
-    RefPtrWillBeMember<MemoryInfo> m_memory;
+    PersistentWillBeMember<MemoryInfo> m_memory;
 };
 
 } // namespace blink
 
 #endif // ConsoleMemory_h