[Oilpan] Prepare full definition of classes before using Member

third_party/WebKit/Source/core/events/PopStateEvent.cpp

Index: third_party/WebKit/Source/core/events/PopStateEvent.cpp
diff --git a/third_party/WebKit/Source/core/events/PopStateEvent.cpp b/third_party/WebKit/Source/core/events/PopStateEvent.cpp
index 50075b6ce78b2d5f387e16fa5b6480677b813738..b1155cd7bd170b5ae998766cc5401c4a4bdd544a 100644
--- a/third_party/WebKit/Source/core/events/PopStateEvent.cpp
+++ b/third_party/WebKit/Source/core/events/PopStateEvent.cpp
@@ -73,6 +73,11 @@ PassRefPtrWillBeRawPtr<PopStateEvent> PopStateEvent::create(const AtomicString&
     return adoptRefWillBeNoop(new PopStateEvent(type, initializer));
 }
 
+History* PopStateEvent::history() const
+{
+    return m_history.get();
+}
+
 const AtomicString& PopStateEvent::interfaceName() const
 {
     return EventNames::PopStateEvent;