Oilpan: DOM wrappers don't need to keep persistent handles

Source/bindings/core/v8/V8GCController.h

Index: Source/bindings/core/v8/V8GCController.h
diff --git a/Source/bindings/core/v8/V8GCController.h b/Source/bindings/core/v8/V8GCController.h
index f33beca236049b275547d328bdf776e3467c56c3..3be246f0b543490e97ab86283ccd3b73e5421cf8 100644
--- a/Source/bindings/core/v8/V8GCController.h
+++ b/Source/bindings/core/v8/V8GCController.h
@@ -31,6 +31,7 @@
 #ifndef V8GCController_h
 #define V8GCController_h
 
+#include "platform/heap/Handle.h"
 #include <v8.h>
 
 namespace blink {
@@ -51,6 +52,8 @@ public:
     static Node* opaqueRootForGC(Node*, v8::Isolate*);
 
     static void reportDOMMemoryUsageToV8(v8::Isolate*);
+
+    static void traceDOMWrappers(v8::Isolate*, Visitor*);
 };
 
 }