Oilpan: have Console be on the heap by default.

Source/core/workers/WorkerGlobalScope.h

 /*
  * Copyright (C) 2008, 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 152 matching lines @@
 
     void clearScript() { m_script.clear(); }
     void clearInspector();
 
     static void removeURLFromMemoryCacheInternal(const KURL&);
 
     KURL m_url;
     String m_userAgent;
     V8CacheOptions m_v8CacheOptions;
 
-    mutable RefPtrWillBeMember<WorkerConsole> m_console;
+    mutable PersistentWillBeMember<WorkerConsole> m_console;
     mutable PersistentWillBeMember<WorkerLocation> m_location;
     mutable PersistentWillBeMember<WorkerNavigator> m_navigator;
 
     mutable UseCounter::CountBits m_deprecationWarningBits;
 
     OwnPtr<WorkerScriptController> m_script;
     WorkerThread* m_thread;
 
     RefPtrWillBeMember<WorkerInspectorController> m_workerInspectorController;
     bool m_closing;
@@ skipping 10 matching lines @@
 
     unsigned long m_workerExceptionUniqueIdentifier;
     WillBeHeapHashMap<unsigned long, RefPtrWillBeMember<ConsoleMessage>> m_pendingMessages;
 };
 
 DEFINE_TYPE_CASTS(WorkerGlobalScope, ExecutionContext, context, context->isWorkerGlobalScope(), context.isWorkerGlobalScope());
 
 } // namespace blink
 
 #endif // WorkerGlobalScope_h