Use DOMSettableTokenList for {HTMLAnchorElement, HTMLAreaElement}.ping.

Source/core/html/HTMLAnchorElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2007, 2008, 2009, 2010 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef HTMLAnchorElement_h
 #define HTMLAnchorElement_h
 
 #include "core/CoreExport.h"
 #include "core/HTMLNames.h"
+#include "core/dom/DOMSettableTokenList.h"
 #include "core/dom/DOMURLUtils.h"
 #include "core/dom/Document.h"
 #include "core/html/HTMLElement.h"
 #include "platform/LinkHash.h"
 
 namespace blink {
 
 // Link relation bitmask values.
 // FIXME: Uncomment as the various link relations are implemented.
 enum {
@@ skipping 10 matching lines @@
 //     RelationNext        = 0x00000400,
 //     RelationNoFolow    = 0x00000800,
     RelationNoReferrer     = 0x00001000,
 //     RelationPrev        = 0x00002000,
 //     RelationSearch      = 0x00004000,
 //     RelationSidebar     = 0x00008000,
 //     RelationTag         = 0x00010000,
 //     RelationUp          = 0x00020000,
 };
 
-class CORE_EXPORT HTMLAnchorElement : public HTMLElement, public DOMURLUtils {
+class CORE_EXPORT HTMLAnchorElement : public HTMLElement, public DOMURLUtils, public DOMSettableTokenListObserver {

[tkent, 2015/07/14 00:29:44]

should be |private DOMSettableTokenListObserver| because HTMLAnchorElement
object doesn't need to behave as a DOMSettableTokenListObserver publicly.

     DEFINE_WRAPPERTYPEINFO();
 public:
+    DECLARE_VIRTUAL_TRACE();
     static PassRefPtrWillBeRawPtr<HTMLAnchorElement> create(Document&);
 
     ~HTMLAnchorElement() override;
 
     KURL href() const;
     void setHref(const AtomicString&);
 
     const AtomicString& name() const;
 
     KURL url() const final;
     void setURL(const KURL&) final;
 
     String input() const final;
     void setInput(const String&) final;
 
     bool isLiveLink() const final;
 
     bool willRespondToMouseClickEvents() final;
 
     bool hasRel(uint32_t relation) const;
     void setRel(const AtomicString&);
 
     LinkHash visitedLinkHash() const;
     void invalidateCachedVisitedLinkHash() { m_cachedVisitedLinkHash = 0; }
 
     void sendPings(const KURL& destinationURL) const;
 
+    DOMSettableTokenList* ping() const;
+
 protected:
     HTMLAnchorElement(const QualifiedName&, Document&);
 
     void attributeWillChange(const QualifiedName&, const AtomicString& oldValue, const AtomicString& newValue) override;
     void parseAttribute(const QualifiedName&, const AtomicString&) override;
     bool supportsFocus() const override;
 
 private:
     bool shouldHaveFocusAppearance() const final;
     void dispatchFocusEvent(Element* oldFocusedElement, WebFocusType) override;
     void dispatchBlurEvent(Element* newFocusedElement, WebFocusType) override;
     bool isMouseFocusable() const override;
     bool isKeyboardFocusable() const override;
     void defaultEventHandler(Event*) final;
     void setActive(bool = true) final;
     void accessKeyAction(bool sendMouseEvents) final;
     bool isURLAttribute(const Attribute&) const final;
     bool hasLegalLinkAttribute(const QualifiedName&) const final;
     bool canStartSelection() const final;
     short tabIndex() const final;
     bool draggable() const final;
     bool isInteractiveContent() const final;
     InsertionNotificationRequest insertedInto(ContainerNode*) override;
     void handleClick(Event*);
 
+    // DOMSettableTokenListObserver
+    virtual void valueChanged() override;

[tkent, 2015/07/14 00:29:44]

|virtual| is not necessary.

+
     uint32_t m_linkRelations;
     mutable LinkHash m_cachedVisitedLinkHash;
     bool m_wasFocusedByMouse;
+    RefPtrWillBeMember<DOMSettableTokenList> m_ping;
 };
 
 inline LinkHash HTMLAnchorElement::visitedLinkHash() const
 {
     if (!m_cachedVisitedLinkHash)
         m_cachedVisitedLinkHash = blink::visitedLinkHash(document().baseURL(), fastGetAttribute(HTMLNames::hrefAttr));
     return m_cachedVisitedLinkHash;
 }
 
 // Functions shared with the other anchor elements (i.e., SVG).
 
 bool isEnterKeyKeydownEvent(Event*);
 bool isLinkClick(Event*);
 
 } // namespace blink
 
 #endif // HTMLAnchorElement_h