Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXListBox.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 21 matching lines @@
 #include "core/html/HTMLOptionElement.h"
 #include "core/html/HTMLSelectElement.h"
 #include "core/layout/LayoutListBox.h"
 #include "modules/accessibility/AXListBoxOption.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
-AXListBox::AXListBox(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXListBox::AXListBox(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
     , m_activeIndex(-1)
 {
     activeIndexChanged();
 }
 
 AXListBox::~AXListBox()
 {
 }
 
-PassRefPtr<AXListBox> AXListBox::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXListBox> AXListBox::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXListBox(layoutObject, axObjectCache));
 }
 
 AccessibilityRole AXListBox::determineAccessibilityRole()
 {
     if ((m_ariaRole = determineAriaRoleAttribute()) != UnknownRole)
         return m_ariaRole;
 
     return ListBoxRole;
 }
 
 AXObject* AXListBox::activeDescendant() const
 {
     if (!isHTMLSelectElement(node()))
         return nullptr;
 
     HTMLSelectElement* select = toHTMLSelectElement(node());
     int activeIndex = select->activeSelectionEndListIndex();
     if (activeIndex >= 0 && activeIndex < static_cast<int>(select->length())) {
         HTMLOptionElement* option = select->item(m_activeIndex);
-        return axObjectCache()->get(option);
+        return axObjectCache().get(option);
     }
 
     return nullptr;
 }
 
 void AXListBox::activeIndexChanged()
 {
     if (!isHTMLSelectElement(node()))
         return;
 
     HTMLSelectElement* select = toHTMLSelectElement(node());
     int activeIndex = select->activeSelectionEndListIndex();
     if (activeIndex == m_activeIndex)
         return;
 
     m_activeIndex = activeIndex;
     if (!select->focused())
         return;
 
     if (m_activeIndex >= 0 && m_activeIndex < static_cast<int>(select->length())) {
         HTMLOptionElement* option = select->item(m_activeIndex);
-        axObjectCache()->postNotification(option, AXObjectCacheImpl::AXFocusedUIElementChanged);
+        axObjectCache().postNotification(option, AXObjectCacheImpl::AXFocusedUIElementChanged);
     } else {
-        axObjectCache()->postNotification(this, AXObjectCacheImpl::AXFocusedUIElementChanged);
+        axObjectCache().postNotification(this, AXObjectCacheImpl::AXFocusedUIElementChanged);
     }
 }
 
 } // namespace blink