Add a new mechanism for watching SVGElement 'href' targets

third_party/WebKit/Source/core/svg/SVGURIReference.h

 /*
  * Copyright (C) 2004, 2005, 2008, 2009 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  *
  * 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 SVGURIReference_h
 #define SVGURIReference_h
 
+#include <memory>
 #include "core/CoreExport.h"
 #include "core/dom/Document.h"
 #include "core/svg/SVGAnimatedHref.h"
 #include "platform/heap/Handle.h"
+#include "wtf/Functional.h"
 
 namespace blink {
 
 class Element;
+class IdTargetObserver;
 
 class CORE_EXPORT SVGURIReference : public GarbageCollectedMixin {
  public:
   virtual ~SVGURIReference() {}
 
   bool isKnownAttribute(const QualifiedName&);
 
   // Use this for accesses to 'href' or 'xlink:href' (in that order) for
   // elements where both are allowed and don't necessarily inherit from
   // SVGURIReference.
   static const AtomicString& legacyHrefString(const SVGElement&);
 
   // Like above, but for elements that inherit from SVGURIReference. Resolves
   // against the base URL of the passed Document.
   KURL legacyHrefURL(const Document&) const;
 
   static AtomicString fragmentIdentifierFromIRIString(const String&,
                                                       const TreeScope&);
   static Element* targetElementFromIRIString(const String&,
                                              const TreeScope&,
                                              AtomicString* = nullptr);
 
   const String& hrefString() const { return m_href->currentValue()->value(); }
 
+  // Create an 'id' observer for the href associated with this SVGURIReference
+  // and its corresponding SVGElement (which should be passed as
+  // |contextElement|.) Will call buildPendingResource() on |contextElement|
+  // when changes to the 'id' are noticed.
+  Element* observeTarget(Member<IdTargetObserver>&, SVGElement&);
+  // Unregister and destroy the observer.
+  static void unobserveTarget(Member<IdTargetObserver>&);
+
   // JS API
   SVGAnimatedHref* href() const { return m_href.get(); }
 
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   explicit SVGURIReference(SVGElement*);
 
  private:
   Member<SVGAnimatedHref> m_href;
@@ skipping 14 matching lines @@
  private:
   const String& m_relativeUrl;
   Member<const Document> m_document;
   mutable KURL m_absoluteUrl;
   bool m_isLocal;
 };
 
 }  // namespace blink
 
 #endif  // SVGURIReference_h