Introduce typed Node/Element iterators for range-based for loops of C++11.

Source/core/dom/ElementTraversal.h

Index: Source/core/dom/ElementTraversal.h
diff --git a/Source/core/dom/ElementTraversal.h b/Source/core/dom/ElementTraversal.h
index c5a39068ce5c6abc6801fbee57fdc919c7cd1865..3d24b383ad877ab32524b92c96a2615be8e11081 100644
--- a/Source/core/dom/ElementTraversal.h
+++ b/Source/core/dom/ElementTraversal.h
@@ -34,6 +34,7 @@ namespace blink {
 template <class ElementType>
 class Traversal {
 public:
+    using TraversalNodeType = ElementType;
     // First or last ElementType child of the node.
     static ElementType* firstChild(const ContainerNode& current) { return firstChildTemplate(current); }
     static ElementType* firstChild(const Node& current) { return firstChildTemplate(current); }
@@ -94,6 +95,11 @@ public:
     template <class MatchFunc>
     static ElementType* nextSibling(const Node&, MatchFunc);
 
+    static TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>> childrenOf(const Node&);
+    static TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>> descendantsOf(const Node&);
+    static TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>> inclusiveDescendantsOf(const ElementType&);
+    static TraversalRange<TraversalNextIterator<Traversal<ElementType>>> fromNext(const Node&);
+
 private:
     template <class NodeType>
     static ElementType* firstChildTemplate(NodeType&);
@@ -113,6 +119,30 @@ private:
 
 typedef Traversal<Element> ElementTraversal;
 
+template <class ElementType>
+inline TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>> Traversal<ElementType>::childrenOf(const Node& start)
+{
+    return TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>>(start);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>> Traversal<ElementType>::descendantsOf(const Node& root)
+{
+    return TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>>(root);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>> Traversal<ElementType>::inclusiveDescendantsOf(const ElementType& root)
+{
+    return TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>>(root);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalNextIterator<Traversal<ElementType>>> Traversal<ElementType>::fromNext(const Node& start)

[dglazkov, 2014/10/21 16:03:11]

This name had stumped me a little bit. What does it mean? :)

[hayato, 2014/10/22 05:15:18]

NodeTraversal::startsFromNext might be better?

Another idea is to remove `fromNext` and let clients use NodeTraversal::from()
instead of NodeTraversal::fromNext().

The means we would replace:

  for (Node& node : NodeTraversal::fromNext(start))

with

 for (Node& node : NodeTraversal::from(NodeTraversal::next(start)))

WDYT?

I am also feeling that NodeTraversal::from(const Node&) is not a good name.
NodeTraversal::startsFrom(const Node*) might be better?

+{
+    return TraversalRange<TraversalNextIterator<Traversal<ElementType>>>(start);
+};
+
 // Specialized for pure Element to exploit the fact that Elements parent is always either another Element or the root.
 template <>
 template <class NodeType>