[oilpan] Make the oilpan branch build on Mac.

Source/core/dom/DocumentEventQueue.cpp

Index: Source/core/dom/DocumentEventQueue.cpp
diff --git a/Source/core/dom/DocumentEventQueue.cpp b/Source/core/dom/DocumentEventQueue.cpp
index 83e0784a86cb5a819e2e99cb109cc40aecfae8cc..75765b84483f5a140e0a814908d17a1c0fa7395f 100644
--- a/Source/core/dom/DocumentEventQueue.cpp
+++ b/Source/core/dom/DocumentEventQueue.cpp
@@ -158,7 +158,7 @@ void DocumentEventQueue::dispatchEvent(PassRefPtr<Event> event)
 {
     EventTarget* eventTarget = event->target();
     if (eventTarget->toDOMWindow())
-        eventTarget->toDOMWindow()->dispatchEvent(event, 0);
+        eventTarget->toDOMWindow()->dispatchEvent(event, Handle<Document>(nullptr));
     else
         eventTarget->dispatchEvent(event);
 }