Use DOMSettableTokenList for {HTMLAnchorElement, HTMLAreaElement}.ping.

Source/core/html/HTMLAnchorElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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 29 matching lines @@
 
 namespace blink {
 
 using namespace HTMLNames;
 
 HTMLAnchorElement::HTMLAnchorElement(const QualifiedName& tagName, Document& document)
     : HTMLElement(tagName, document)
     , m_linkRelations(0)
     , m_cachedVisitedLinkHash(0)
     , m_wasFocusedByMouse(false)
+    , m_ping(DOMSettableTokenList::create(this))
 {
 }
 
+DEFINE_TRACE(HTMLAnchorElement)
+{
+    visitor->trace(m_ping);
+    HTMLElement::trace(visitor);
+    DOMSettableTokenListObserver::trace(visitor);
+}
+
 PassRefPtrWillBeRawPtr<HTMLAnchorElement> HTMLAnchorElement::create(Document& document)
 {
     return adoptRefWillBeNoop(new HTMLAnchorElement(aTag, document));
 }
 
 HTMLAnchorElement::~HTMLAnchorElement()
 {
+    m_ping->setObserver(nullptr);

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

This doesn't work on Oilpan because m_ping can be destructed before |this|.  On
Oilpan, DOMSettableTokenList::m_observer is a weak member, so we don't need to
do anything here.
We need #if here.

#if !ENABLE(OILPAN)
    m_ping->setObserver(nullptr)+
#endif

 }
 
 bool HTMLAnchorElement::supportsFocus() const
 {
     if (hasEditableStyle())
         return HTMLElement::supportsFocus();
     // If not a link we should still be able to focus the element if it has tabIndex.
     return isLink() || HTMLElement::supportsFocus();
 }
 
@@ skipping 140 matching lines @@
             if (document().isDNSPrefetchEnabled()) {
                 if (protocolIs(parsedURL, "http") || protocolIs(parsedURL, "https") || parsedURL.startsWith("//"))
                     prefetchDNS(document().completeURL(parsedURL).host());
             }
         }
         invalidateCachedVisitedLinkHash();
     } else if (name == nameAttr || name == titleAttr) {
         // Do nothing.
     } else if (name == relAttr) {
         setRel(value);
+    } else if (name == pingAttr) {
+        m_ping->setValue(value);
     } else {
         HTMLElement::parseAttribute(name, value);
     }
 }
 
 void HTMLAnchorElement::accessKeyAction(bool sendMouseEvents)
 {
     dispatchSimulatedClick(0, sendMouseEvents ? SendMouseUpDownEvents : SendNoEvents);
 }
 
@@ skipping 80 matching lines @@
     return Element::tabIndex();
 }
 
 bool HTMLAnchorElement::isLiveLink() const
 {
     return isLink() && !hasEditableStyle();
 }
 
 void HTMLAnchorElement::sendPings(const KURL& destinationURL) const
 {
-    const AtomicString& pingValue = getAttribute(pingAttr);
-    if (pingValue.isNull() || !document().settings() || !document().settings()->hyperlinkAuditingEnabled())
+    if (m_ping->value().isNull() || !document().settings() || !document().settings()->hyperlinkAuditingEnabled())
         return;
 
     UseCounter::count(document(), UseCounter::HTMLAnchorElementPingAttribute);
 
-    SpaceSplitString pingURLs(pingValue, SpaceSplitString::ShouldNotFoldCase);
+    SpaceSplitString pingURLs = m_ping->tokens();

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

should be |const SpaceSplitString&|.

     for (unsigned i = 0; i < pingURLs.size(); i++)
         PingLoader::sendLinkAuditPing(document().frame(), document().completeURL(pingURLs[i]), destinationURL);
 }
 
+DOMSettableTokenList* HTMLAnchorElement::ping() const
+{
+    return m_ping.get();
+}
+
 void HTMLAnchorElement::handleClick(Event* event)
 {
     event->setDefaultHandled();
 
     LocalFrame* frame = document().frame();
     if (!frame)
         return;
 
     StringBuilder url;
     url.append(stripLeadingAndTrailingHTMLSpaces(fastGetAttribute(hrefAttr)));
@@ skipping 50 matching lines @@
         if (activityLogger) {
             Vector<String> argv;
             argv.append("a");
             argv.append(fastGetAttribute(hrefAttr));
             activityLogger->logEvent("blinkAddElement", argv.size(), argv.data());
         }
     }
     return HTMLElement::insertedInto(insertionPoint);
 }
 
+void HTMLAnchorElement::valueChanged()
+{
+    setSynchronizedLazyAttribute(pingAttr, m_ping->value());
+}
+
 } // namespace blink