Have HTMLCollection::item() return an Element as per specification

Source/bindings/v8/V8WindowShell.cpp

Index: Source/bindings/v8/V8WindowShell.cpp
diff --git a/Source/bindings/v8/V8WindowShell.cpp b/Source/bindings/v8/V8WindowShell.cpp
index 7b8cdd9db2973657c8d83d164c1060e2481e24c7..6013354c9de185357b3fb25f03d80cf38f7e1540 100644
--- a/Source/bindings/v8/V8WindowShell.cpp
+++ b/Source/bindings/v8/V8WindowShell.cpp
@@ -444,11 +444,11 @@ static v8::Handle<v8::Value> getNamedProperty(HTMLDocument* htmlDocument, const
         return v8Undefined();
 
     if (items->hasExactlyOneItem()) {
-        Node* node = items->item(0);
+        Element* element = items->item(0);
         Frame* frame = 0;
-        if (node->hasTagName(HTMLNames::iframeTag) && (frame = toHTMLIFrameElement(node)->contentFrame()))
+        if (element->hasTagName(HTMLNames::iframeTag) && (frame = toHTMLIFrameElement(element)->contentFrame()))
             return toV8(frame->domWindow(), creationContext, isolate);
-        return toV8(node, creationContext, isolate);
+        return toV8(element, creationContext, isolate);
     }
     return toV8(items.release(), creationContext, isolate);
 }