Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXList.cpp

 /*
  * Copyright (C) 2008 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
@@ skipping 19 matching lines @@
 #include "modules/accessibility/AXList.h"
 
 #include "core/html/HTMLUListElement.h"
 #include "core/layout/LayoutObject.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
-AXList::AXList(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXList::AXList(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
 {
 }
 
 AXList::~AXList()
 {
 }
 
-PassRefPtr<AXList> AXList::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXList> AXList::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXList(layoutObject, axObjectCache));
 }
 
 bool AXList::computeAccessibilityIsIgnored(IgnoredReasons* ignoredReasons) const
 {
     return accessibilityIsIgnoredByDefault(ignoredReasons);
 }
 
 bool AXList::isDescriptionList() const
 {
     if (!m_layoutObject)
         return false;
 
     Node* node = m_layoutObject->node();
     return node && node->hasTagName(dlTag);
 }
 
 AccessibilityRole AXList::roleValue() const
 {
     if (isDescriptionList())
         return DescriptionListRole;
 
     return ListRole;
 }
 } // namespace blink