Make SelectorChecker a const operation over element.

sky/engine/core/dom/Element.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003-2011, 2013, 2014 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 198 matching lines @@
 
     ElementShadow* shadow() const;
     ElementShadow& ensureShadow();
     PassRefPtr<ShadowRoot> ensureShadowRoot(ExceptionState&);
     ShadowRoot* shadowRoot() const;
 
     bool hasAuthorShadowRoot() const { return shadowRoot(); }
 
     RenderStyle* computedStyle(PseudoId = NOPSEUDO);
 
-    bool isUpgradedCustomElement() { return customElementState() == Upgraded; }
-    bool isUnresolvedCustomElement() { return customElementState() == WaitingForUpgrade; }
+    bool isUpgradedCustomElement() const { return customElementState() == Upgraded; }
+    bool isUnresolvedCustomElement() const { return customElementState() == WaitingForUpgrade; }
 
     AtomicString computeInheritedLanguage() const;
 
     virtual bool isURLAttribute(const Attribute&) const { return false; }
 
     virtual bool isLiveLink() const { return false; }
     KURL hrefURL() const;
 
     KURL getURLAttribute(const QualifiedName&) const;
     KURL getNonEmptyURLAttribute(const QualifiedName&) const;
@@ skipping 369 matching lines @@
     static PassRefPtr<T> create(const QualifiedName&, Document&)
 #define DEFINE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
     PassRefPtr<T> T::create(const QualifiedName& tagName, Document& document) \
     { \
         return adoptRef(new T(tagName, document)); \
     }
 
 } // namespace
 
 #endif  // SKY_ENGINE_CORE_DOM_ELEMENT_H_