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

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 4206 matching lines @@
         return KURL();
 
     // FIXME: Why do we need to wait for FrameStateComplete?
     if (frame()->loader().state() != FrameStateComplete)
         return KURL();
 
     if (!head())
         return KURL();
 
     RefPtr<HTMLCollection> children = head()->children();
-    for (unsigned i = 0; Node* child = children->item(i); i++) {
+    for (unsigned i = 0; Element* child = children->item(i); i++) {
         if (!child->hasTagName(linkTag))
             continue;
         HTMLLinkElement* linkElement = toHTMLLinkElement(child);
         if (!equalIgnoringCase(linkElement->type(), openSearchMIMEType) || !equalIgnoringCase(linkElement->rel(), openSearchRelation))
             continue;
         if (linkElement->href().isEmpty())
             continue;
         return linkElement->href();
     }
 
@@ skipping 237 matching lines @@
 {
     IconURL firstFavicon;
     IconURL firstTouchIcon;
     IconURL firstTouchPrecomposedIcon;
     Vector<IconURL> secondaryIcons;
 
     // Start from the last child node so that icons seen later take precedence as required by the spec.
     RefPtr<HTMLCollection> children = head() ? head()->children() : 0;
     unsigned length = children ? children->length() : 0;
     for (unsigned i = 0; i < length; i++) {
-        Node* child = children->item(i);
+        Element* child = children->item(i);
         if (!child->hasTagName(linkTag))
             continue;
         HTMLLinkElement* linkElement = toHTMLLinkElement(child);
         if (!(linkElement->iconType() & iconTypesMask))
             continue;
         if (linkElement->href().isEmpty())
             continue;
         if (!RuntimeEnabledFeatures::touchIconLoadingEnabled() && linkElement->iconType() != Favicon)
             continue;
 
@@ skipping 931 matching lines @@
 void Document::defaultEventHandler(Event* event)
 {
     if (frame() && frame()->remotePlatformLayer()) {
         frame()->chromeClient().forwardInputEvent(this, event);
         return;
     }
     Node::defaultEventHandler(event);
 }
 
 } // namespace WebCore