Use NodeTraversal to iterate over the accessibility nodes

Source/modules/accessibility/AXNodeObject.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 1515 matching lines @@
 {
     // First check if it has a custom rect, for example if this element is tied to a canvas path.
     if (!m_explicitElementRect.isEmpty())
         return m_explicitElementRect;
 
     // FIXME: If there are a lot of elements in the canvas, it will be inefficient.
     // We can avoid the inefficient calculations by using AXComputedObjectAttributeCache.
     if (node()->parentElement()->isInCanvasSubtree()) {
         LayoutRect rect;
 
-        for (Node* child = node()->firstChild(); child; child = child->nextSibling()) {
-            if (child->isHTMLElement()) {
-                if (AXObject* obj = axObjectCache()->get(child)) {
+        for (Node& child : NodeTraversal::childrenOf(*node())) {
+            if (child.isHTMLElement()) {
+                if (AXObject* obj = axObjectCache()->get(&child)) {
                     if (rect.isEmpty())
                         rect = obj->elementRect();
                     else
                         rect.unite(obj->elementRect());
                 }
             }
         }
 
         if (!rect.isEmpty())
             return rect;
@@ skipping 74 matching lines @@
 
     if (!m_node)
         return;
 
     m_haveChildren = true;
 
     // The only time we add children from the DOM tree to a node with a layoutObject is when it's a canvas.
     if (layoutObject() && !isHTMLCanvasElement(*m_node))
         return;
 
-    for (Node* child = m_node->firstChild(); child; child = child->nextSibling())
-        addChild(axObjectCache()->getOrCreate(child));
+    for (Node& child : NodeTraversal::childrenOf(*m_node))
+        addChild(axObjectCache()->getOrCreate(&child));
 
     for (unsigned i = 0; i < m_children.size(); ++i)
         m_children[i].get()->setParent(this);
 }
 
 void AXNodeObject::addChild(AXObject* child)
 {
     insertChild(child, m_children.size());
 }
 
@@ skipping 347 matching lines @@
     float range = maxValueForRange() - minValueForRange();
     float value = valueForRange();
 
     value += range * (percentChange / 100);
     setValue(String::number(value));
 
     axObjectCache()->postNotification(node(), AXObjectCacheImpl::AXValueChanged, true);
 }
 
 } // namespace blink