Enable Oilpan for core/timing/.

Source/modules/performance/WorkerPerformance.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 24 matching lines @@
 #include "core/workers/DedicatedWorkerGlobalScope.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
 WorkerPerformance::WorkerPerformance()
 {
 }
 
+DEFINE_TRACE(WorkerPerformance)
+{
+    visitor->trace(m_memoryInfo);
+}
+
 double WorkerPerformance::now(ExecutionContext* context) const
 {
     ASSERT(context);
     ASSERT(context->isWorkerGlobalScope());
     WorkerGlobalScope* workerGlobalScope = toWorkerGlobalScope(context);
     return 1000.0 * (monotonicallyIncreasingTime() - workerGlobalScope->timeOrigin());
 }
 
-PassRefPtrWillBeRawPtr<MemoryInfo> WorkerPerformance::memory() const
+MemoryInfo* WorkerPerformance::memory()
 {
-    // FIXME: We shall not create a new object every time.
-    return MemoryInfo::create();
+    if (!m_memoryInfo)
+        m_memoryInfo = MemoryInfo::create();
+
+    return m_memoryInfo.get();
 }
 
 } // namespace blink