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

public/web/WebNodeCollection.h

Index: public/web/WebNodeCollection.h
diff --git a/public/web/WebNodeCollection.h b/public/web/WebNodeCollection.h
index d2f0465ab1521f7af284546ab4e45621f770d115..74938791fb4570b66fe44698203673454f8d29ec 100644
--- a/public/web/WebNodeCollection.h
+++ b/public/web/WebNodeCollection.h
@@ -39,7 +39,7 @@ namespace WTF { template <typename T> class PassRefPtr; }
 #endif
 
 namespace blink {
-class WebNode;
+class WebElement;
 
 // Provides readonly access to some properties of a DOM node.
 class WebNodeCollection {
@@ -60,8 +60,8 @@ public:
     BLINK_EXPORT void assign(const WebNodeCollection&);
 
     BLINK_EXPORT unsigned length() const;
-    BLINK_EXPORT WebNode nextItem() const;
-    BLINK_EXPORT WebNode firstItem() const;
+    BLINK_EXPORT WebElement nextItem() const;
+    BLINK_EXPORT WebElement firstItem() const;
 
 #if BLINK_IMPLEMENTATION
     WebNodeCollection(const WTF::PassRefPtr<WebCore::HTMLCollection>&);