WIP (Introduce WTF::NonNullPtr<T>.)

Source/core/accessibility/AccessibilityNodeObject.cpp

 /*
 * Copyright (C) 2012, Google 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 241 matching lines @@
 
     return UnknownRole;
 }
 
 void AccessibilityNodeObject::elementsFromAttribute(Vector<Element*>& elements, const QualifiedName& attribute) const
 {
     Node* node = this->node();
     if (!node || !node->isElementNode())
         return;
 
-    TreeScope& scope = node->treeScope();
+    NonNullPtr<TreeScope> scope = node->treeScope();
 
     String idList = getAttribute(attribute).string();
     if (idList.isEmpty())
         return;
 
     idList.replace('\n', ' ');
     Vector<String> idVector;
     idList.split(' ', idVector);
 
     unsigned size = idVector.size();
     for (unsigned i = 0; i < size; ++i) {
         AtomicString idName(idVector[i]);
-        Element* idElement = scope.getElementById(idName);
+        Element* idElement = scope->getElementById(idName);
         if (idElement)
             elements.append(idElement);
     }
 }
 
 // If you call node->rendererIsEditable() since that will return true if an ancestor is editable.
 // This only returns true if this is the element that actually has the contentEditable attribute set.
 bool AccessibilityNodeObject::hasContentEditableAttributeSet() const
 {
     if (!hasAttribute(contenteditableAttr))
@@ skipping 48 matching lines @@
     return true;
 }
 
 HTMLLabelElement* AccessibilityNodeObject::labelForElement(Element* element) const
 {
     if (!element->isHTMLElement() || !toHTMLElement(element)->isLabelable())
         return 0;
 
     const AtomicString& id = element->getIdAttribute();
     if (!id.isEmpty()) {
-        if (HTMLLabelElement* label = element->treeScope().labelElementForId(id))
+        if (HTMLLabelElement* label = element->treeScope()->labelElementForId(id))
             return label;
     }
 
     for (Element* parent = element->parentElement(); parent; parent = parent->parentElement()) {
         if (isHTMLLabelElement(parent))
             return toHTMLLabelElement(parent);
     }
 
     return 0;
 }
@@ skipping 1442 matching lines @@
         useTextUnderElement = true;
 
     if (useTextUnderElement) {
         String text = textUnderElement();
         if (!text.isEmpty())
             textOrder.append(AccessibilityText(text, ChildrenText));
     }
 }
 
 } // namespace WebCore