Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXSlider.cpp

 /*
  * Copyright (C) 2009 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/dom/shadow/ShadowRoot.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/shadow/ShadowElementNames.h"
 #include "core/layout/LayoutObject.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
-AXSlider::AXSlider(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXSlider::AXSlider(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
 {
 }
 
-PassRefPtr<AXSlider> AXSlider::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXSlider> AXSlider::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXSlider(layoutObject, axObjectCache));
 }
 
 AccessibilityRole AXSlider::determineAccessibilityRole()
 {
     if ((m_ariaRole = determineAriaRoleAttribute()) != UnknownRole)
         return m_ariaRole;
 
     return SliderRole;
@@ skipping 26 matching lines @@
         return AccessibilityOrientationHorizontal;
     }
 }
 
 void AXSlider::addChildren()
 {
     ASSERT(!m_haveChildren);
 
     m_haveChildren = true;
 
-    AXObjectCacheImpl* cache = axObjectCache();
+    AXObjectCacheImpl& cache = axObjectCache();
 
-    AXSliderThumb* thumb = static_cast<AXSliderThumb*>(cache->getOrCreate(SliderThumbRole));
+    AXSliderThumb* thumb = static_cast<AXSliderThumb*>(cache.getOrCreate(SliderThumbRole));
     thumb->setParent(this);
 
     // Before actually adding the value indicator to the hierarchy,
     // allow the platform to make a final decision about it.
     if (thumb->accessibilityIsIgnored())
-        cache->remove(thumb->axObjectID());
+        cache.remove(thumb->axObjectID());
     else
         m_children.append(thumb);
 }
 
 const AtomicString& AXSlider::getAttribute(const QualifiedName& attribute) const
 {
     return element()->getAttribute(attribute);
 }
 
 AXObject* AXSlider::elementAccessibilityHitTest(const IntPoint& point) const
 {
     if (m_children.size()) {
         ASSERT(m_children.size() == 1);
         if (m_children[0]->elementRect().contains(point))
             return m_children[0].get();
     }
 
-    return axObjectCache()->getOrCreate(m_layoutObject);
+    return axObjectCache().getOrCreate(m_layoutObject);
 }
 
 void AXSlider::setValue(const String& value)
 {
     HTMLInputElement* input = element();
 
     if (input->value() == value)
         return;
 
     input->setValue(value);
 
     // Fire change event manually, as LayoutSlider::setValueForPosition does.
     input->dispatchFormControlChangeEvent();
 }
 
 HTMLInputElement* AXSlider::element() const
 {
     return toHTMLInputElement(m_layoutObject->node());
 }
 
-AXSliderThumb::AXSliderThumb(AXObjectCacheImpl* axObjectCache)
+AXSliderThumb::AXSliderThumb(AXObjectCacheImpl& axObjectCache)
     : AXMockObject(axObjectCache)
 {
 }
 
-PassRefPtr<AXSliderThumb> AXSliderThumb::create(AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXSliderThumb> AXSliderThumb::create(AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXSliderThumb(axObjectCache));
 }
 
 LayoutRect AXSliderThumb::elementRect() const
 {
     if (!m_parent)
         return LayoutRect();
 
     LayoutObject* sliderLayoutObject = m_parent->layoutObject();
     if (!sliderLayoutObject || !sliderLayoutObject->isSlider())
         return LayoutRect();
     return toElement(sliderLayoutObject->node())->userAgentShadowRoot()->getElementById(ShadowElementNames::sliderThumb())->boundingBox();
 }
 
 bool AXSliderThumb::computeAccessibilityIsIgnored(IgnoredReasons* ignoredReasons) const
 {
     return accessibilityIsIgnoredByDefault(ignoredReasons);
 }
 
 } // namespace blink