Introduce isHTMLLabelElement and toHTMLLabelElement

Source/core/accessibility/AXObjectCache.cpp

 /*
  * Copyright (C) 2008, 2009, 2010 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 773 matching lines @@
         obj->notifyIfIgnoredValueChanged();
     }
 }
 
 void AXObjectCache::handleAttributeChanged(const QualifiedName& attrName, Element* element)
 {
     if (attrName == roleAttr)
         handleAriaRoleChanged(element);
     else if (attrName == altAttr || attrName == titleAttr)
         textChanged(element);
-    else if (attrName == forAttr && element->hasTagName(labelTag))
+    else if (attrName == forAttr && isHTMLLabelElement(element))
         labelChanged(element);
 
     if (!attrName.localName().string().startsWith("aria-"))
         return;
 
     if (attrName == aria_activedescendantAttr)
         handleActiveDescendantChanged(element);
     else if (attrName == aria_valuenowAttr || attrName == aria_valuetextAttr)
         postNotification(element, AXObjectCache::AXValueChanged, true);
     else if (attrName == aria_labelAttr || attrName == aria_labeledbyAttr || attrName == aria_labelledbyAttr)
         textChanged(element);
     else if (attrName == aria_checkedAttr)
         checkedStateChanged(element);
     else if (attrName == aria_selectedAttr)
         selectedChildrenChanged(element);
     else if (attrName == aria_expandedAttr)
         handleAriaExpandedChange(element);
     else if (attrName == aria_hiddenAttr)
         childrenChanged(element->parentNode());
     else if (attrName == aria_invalidAttr)
         postNotification(element, AXObjectCache::AXInvalidStatusChanged, true);
     else
         postNotification(element, AXObjectCache::AXAriaAttributeChanged, true);
 }
 
 void AXObjectCache::labelChanged(Element* element)
 {
-    ASSERT(element->hasTagName(labelTag));
-    HTMLElement* correspondingControl = static_cast<HTMLLabelElement*>(element)->control();
-    textChanged(correspondingControl);
+    textChanged(toHTMLLabelElement(element)->control());
 }
 
 void AXObjectCache::recomputeIsIgnored(RenderObject* renderer)
 {
     if (AccessibilityObject* obj = get(renderer))
         obj->notifyIfIgnoredValueChanged();
 }
 
 void AXObjectCache::startCachingComputedObjectAttributesUntilTreeMutates()
 {
@@ skipping 186 matching lines @@
 void AXObjectCache::handleScrolledToAnchor(const Node* anchorNode)
 {
     // The anchor node may not be accessible. Post the notification for the
     // first accessible object.
     postPlatformNotification(AccessibilityObject::firstAccessibleObjectFromNode(anchorNode), AXScrolledToAnchor);
 }
 
 } // namespace WebCore
 
 #endif // HAVE(ACCESSIBILITY)