Oilpan: Prepare to move AXObjectCache to the heap

Source/core/dom/AXObjectCache.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010, 2011 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 namespace blink {
 class AXObject;
 class FrameView;
 class HTMLOptionElement;
 class HTMLSelectElement;
 class LayoutMenuList;
 class Page;
 class Widget;
 
-class CORE_EXPORT AXObjectCache {
-    WTF_MAKE_NONCOPYABLE(AXObjectCache); WTF_MAKE_FAST_ALLOCATED(AXObjectCache);
+class CORE_EXPORT AXObjectCache : public NoBaseWillBeGarbageCollectedFinalized<AXObjectCache> {
+    WTF_MAKE_NONCOPYABLE(AXObjectCache);
+    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(AXObjectCache);
 public:
-    static PassOwnPtr<AXObjectCache> create(Document&);
+    static PassOwnPtrWillBeRawPtr<AXObjectCache> create(Document&);
 
     static AXObject* focusedUIElementForPage(const Page*);
 
     virtual ~AXObjectCache();
+    DEFINE_INLINE_VIRTUAL_TRACE() { }
 
     enum AXNotification {
         AXActiveDescendantChanged,
         AXAlert,
         AXAriaAttributeChanged,
         AXAutocorrectionOccured,
         AXBlur,
         AXCheckedStateChanged,
         AXChildrenChanged,
         AXFocusedUIElementChanged,
@@ skipping 13 matching lines @@
         AXScrolledToAnchor,
         AXSelectedChildrenChanged,
         AXSelectedTextChanged,
         AXShow,
         AXTextChanged,
         AXTextInserted,
         AXTextRemoved,
         AXValueChanged
     };
 
+    virtual void dispose() = 0;
+
     virtual void selectionChanged(Node*) = 0;
     virtual void childrenChanged(Node*) = 0;
     virtual void childrenChanged(LayoutObject*) = 0;
     virtual void checkedStateChanged(Node*) = 0;
     virtual void listboxOptionStateChanged(HTMLOptionElement*) = 0;
     virtual void listboxSelectedChildrenChanged(HTMLSelectElement*) = 0;
     virtual void listboxActiveIndexChanged(HTMLSelectElement*) = 0;
 
     virtual void remove(LayoutObject*) = 0;
     virtual void remove(Node*) = 0;
@@ skipping 30 matching lines @@
     virtual void handleScrollPositionChanged(LayoutObject*) = 0;
 
     // Called when scroll bars are added / removed (as the view resizes).
     virtual void handleScrollbarUpdate(FrameView*) = 0;
     virtual void handleLayoutComplete(LayoutObject*) = 0;
     virtual void handleScrolledToAnchor(const Node* anchorNode) = 0;
 
     virtual const AtomicString& computedRoleForNode(Node*) = 0;
     virtual String computedNameForNode(Node*) = 0;
 
-    typedef PassOwnPtr<AXObjectCache> (*AXObjectCacheCreateFunction)(Document&);
+    typedef PassOwnPtrWillBeRawPtr<AXObjectCache> (*AXObjectCacheCreateFunction)(Document&);
     static void init(AXObjectCacheCreateFunction);
 
 protected:
     AXObjectCache();
 
 private:
     static AXObjectCacheCreateFunction m_createFunction;
 };
 
-class CORE_EXPORT ScopedAXObjectCache {
+class CORE_EXPORT ScopedAXObjectCache : public NoBaseWillBeGarbageCollectedFinalized<ScopedAXObjectCache> {

[haraken, 2015/05/28 08:57:57]

Is ScopedAXObjectCache used in performance-sensitive places?

If no, we might want to keep ScopedAXObjectCache off-heap. That way we can call
m_cache->dispose() in the destructor of ScopedAXObjectCache. Then we don't need
to call ->dispose() in the call sites of ScopedAXObjectCache.

[keishi, 2015/05/29 09:00:57]

Done.

     WTF_MAKE_NONCOPYABLE(ScopedAXObjectCache);
 public:
-    static PassOwnPtr<ScopedAXObjectCache> create(Document&);
+    static PassOwnPtrWillBeRawPtr<ScopedAXObjectCache> create(Document&);
+    ~ScopedAXObjectCache();
+    DECLARE_TRACE();
+
+    void dispose();
 
     AXObjectCache* get();
 
 private:
     explicit ScopedAXObjectCache(Document&);
 
-    OwnPtr<AXObjectCache> m_ownedCache;
-    AXObjectCache* m_cache;
+    OwnPtrWillBeMember<AXObjectCache> m_ownedCache;
+    RawPtrWillBeMember<AXObjectCache> m_cache;

[haraken, 2015/05/28 08:57:57]

If we keep ScopedAXObjectCache off-heap, we need to use Persistent here (it is
ok as long as ScopedAXObjectCache is not performance-sensitive).

+
+#if ENABLE(ASSERT)
+    // Verified when finalizing.
+    bool m_hasBeenDisposed;
+#endif
 };
 
 }
 
 #endif