Revert of Revert of Oilpan: Prepare to make ExecutionContext GarbageCollectedMixin.

Source/core/dom/ExecutionContext.h

Index: Source/core/dom/ExecutionContext.h
diff --git a/Source/core/dom/ExecutionContext.h b/Source/core/dom/ExecutionContext.h
index c93492dbf87c6e9b36290cb54605142c50bac78e..eb165efd7f87d1e6ec2687816f9eca4c9ebc7920 100644
--- a/Source/core/dom/ExecutionContext.h
+++ b/Source/core/dom/ExecutionContext.h
@@ -38,6 +38,7 @@
 #include "core/frame/DOMTimer.h"
 #include "platform/LifecycleContext.h"
 #include "platform/Supplementable.h"
+#include "platform/heap/Handle.h"
 #include "platform/weborigin/KURL.h"
 #include "wtf/Functional.h"
 #include "wtf/OwnPtr.h"
@@ -60,7 +61,10 @@
 class SecurityOrigin;
 class ScriptCallStack;
 
-class ExecutionContext : public LifecycleContext<ExecutionContext>, public Supplementable<ExecutionContext> {
+class ExecutionContext
+    : public WillBeGarbageCollectedMixin
+    , public LifecycleContext<ExecutionContext>
+    , public Supplementable<ExecutionContext> {
 public:
     ExecutionContext();
     virtual ~ExecutionContext();
@@ -107,9 +111,10 @@
 
     // Called after the construction of an ActiveDOMObject to synchronize suspend state.
     void suspendActiveDOMObjectIfNeeded(ActiveDOMObject*);
-
+#if !ENABLE(OILPAN)
     void ref() { refExecutionContext(); }
     void deref() { derefExecutionContext(); }
+#endif
 
     // Gets the next id in a circular sequence from 1 to 2^31-1.
     int circularSequentialID();
@@ -133,8 +138,10 @@
 
     bool dispatchErrorEvent(PassRefPtrWillBeRawPtr<ErrorEvent>, AccessControlStatus);
 
+#if !ENABLE(OILPAN)
     virtual void refExecutionContext() = 0;
     virtual void derefExecutionContext() = 0;
+#endif
     // LifecycleContext implementation.
 
     // Implementation details for DOMTimer. No other classes should call these functions.