Add a new mechanism for watching SVGElement 'href' targets

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

 /*
  * Copyright (C) 2007 Eric Seidel <eric@webkit.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 SVGMPathElement_h
 #define SVGMPathElement_h
 
-#include "core/SVGNames.h"
 #include "core/svg/SVGElement.h"
 #include "core/svg/SVGURIReference.h"
 
 namespace blink {
 
 class SVGPathElement;
 
 class SVGMPathElement final : public SVGElement, public SVGURIReference {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(SVGMPathElement);
@@ skipping 14 matching lines @@
 
   void buildPendingResource() override;
   void clearResourceReferences();
   InsertionNotificationRequest insertedInto(ContainerNode*) override;
   void removedFrom(ContainerNode*) override;
 
   void svgAttributeChanged(const QualifiedName&) override;
 
   bool layoutObjectIsNeeded(const ComputedStyle&) override { return false; }
   void notifyParentOfPathChange(ContainerNode*);
+
+  Member<IdTargetObserver> m_targetIdObserver;
 };
 
 }  // namespace blink
 
 #endif  // SVGMPathElement_h