Oilpan: Prepare to move AXObjectCache to the heap

Source/modules/accessibility/AXObjectCacheImpl.cpp

 /*
  * Copyright (C) 2014, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 66 matching lines @@
 #include "modules/accessibility/AXTableColumn.h"
 #include "modules/accessibility/AXTableHeaderContainer.h"
 #include "modules/accessibility/AXTableRow.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 // static
-AXObjectCache* AXObjectCacheImpl::create(Document& document)
+PassOwnPtrWillBeRawPtr<AXObjectCache> AXObjectCacheImpl::create(Document& document)
 {
-    return new AXObjectCacheImpl(document);
+    return adoptPtrWillBeNoop(new AXObjectCacheImpl(document));
 }
 
 AXObjectCacheImpl::AXObjectCacheImpl(Document& document)
     : m_document(document)
     , m_modificationCount(0)
+#if ENABLE(ASSERT)
+    , m_hasBeenDisposed(false)
+#endif
     , m_notificationPostTimer(this, &AXObjectCacheImpl::notificationPostTimerFired)
 {
 }
 
 AXObjectCacheImpl::~AXObjectCacheImpl()
 {
+    ASSERT(m_hasBeenDisposed);
+}
+
+void AXObjectCacheImpl::dispose()
+{
     m_notificationPostTimer.stop();
 
     HashMap<AXID, RefPtr<AXObject>>::iterator end = m_objects.end();
     for (HashMap<AXID, RefPtr<AXObject>>::iterator it = m_objects.begin(); it != end; ++it) {
         AXObject* obj = (*it).value.get();
         obj->detach();
         removeAXID(obj);
     }
+
+#if ENABLE(ASSERT)
+    m_hasBeenDisposed = true;
+#endif
 }
 
 AXObject* AXObjectCacheImpl::root()
 {
     return getOrCreate(&m_document);
 }
 
 AXObject* AXObjectCacheImpl::focusedImageMapUIElement(HTMLAreaElement* areaElement)
 {
     // Find the corresponding accessibility object for the HTMLAreaElement. This should be
@@ skipping 1227 matching lines @@
 
 void AXObjectCacheImpl::setCanvasObjectBounds(Element* element, const LayoutRect& rect)
 {
     AXObject* obj = getOrCreate(element);
     if (!obj)
         return;
 
     obj->setElementRect(rect);
 }
 
+DEFINE_TRACE(AXObjectCacheImpl)
+{
+    visitor->template registerWeakMembers<AXObjectCacheImpl, &AXObjectCacheImpl::clearWeakMembers>(this);
+    AXObjectCache::trace(visitor);
+}
+
 } // namespace blink