Use stricter typing for HTMLCollection named getter

Source/core/dom/NamedNodesCollection.h

Index: Source/core/dom/NamedNodesCollection.h
diff --git a/Source/core/dom/NamedNodesCollection.h b/Source/core/dom/NamedNodesCollection.h
index b202bcf238f728c0c1cabf77bae8aaeab45ce61f..bfb1a697bd1159a255ad2582e194ae908c71568c 100644
--- a/Source/core/dom/NamedNodesCollection.h
+++ b/Source/core/dom/NamedNodesCollection.h
@@ -41,7 +41,7 @@ namespace WebCore {
 
 class NamedNodesCollection FINAL : public NodeList {
 public:
-    static PassRefPtr<NodeList> create(const Vector<RefPtr<Node> >& nodes)
+    static PassRefPtr<NodeList> create(const Vector<RefPtr<Element> >& nodes)
     {
         return adoptRef(new NamedNodesCollection(nodes));
     }
@@ -51,10 +51,10 @@ public:
     virtual Node* namedItem(const AtomicString&) const OVERRIDE;
 
 private:
-    explicit NamedNodesCollection(const Vector<RefPtr<Node> >& nodes)
+    explicit NamedNodesCollection(const Vector<RefPtr<Element> >& nodes)
         : m_nodes(nodes) { }
 
-    Vector<RefPtr<Node> > m_nodes;
+    Vector<RefPtr<Element> > m_nodes;
 };
 
 } // namespace WebCore