Oilpan: enable appcache + move DocumentLoader to the heap.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index bb1befff42ad782cca0803922720d80baf23c5b1..8c938ad90fa57e675c92dc2cf925a2b8a717bcc8 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -2653,7 +2653,7 @@ void Document::dispatchUnloadEvents()
             // The DocumentLoader (and thus its DocumentLoadTiming) might get destroyed
             // while dispatching the event, so protect it to prevent writing the end
             // time into freed memory.
-            RefPtr<DocumentLoader> documentLoader =  m_frame->loader().provisionalDocumentLoader();
+            RefPtrWillBeRawPtr<DocumentLoader> documentLoader =  m_frame->loader().provisionalDocumentLoader();
             m_loadEventProgress = UnloadEventInProgress;
             RefPtrWillBeRawPtr<Event> unloadEvent(Event::create(EventTypeNames::unload));
             if (documentLoader && !documentLoader->timing().unloadEventStart() && !documentLoader->timing().unloadEventEnd()) {