[SVG] Shared <use> path geometry

third_party/WebKit/Source/core/svg/SVGPathElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 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,
@@ skipping 54 matching lines @@
 {
     visitor->trace(m_pathLength);
     visitor->trace(m_path);
     SVGGeometryElement::trace(visitor);
 }
 
 DEFINE_NODE_FACTORY(SVGPathElement)
 
 Path SVGPathElement::asPath() const
 {
-    Path path;
-    buildPathFromByteStream(pathByteStream(), path);
-    return path;
+    // If this is a <use> instance, return the referenced path to maximize geometry sharing.
+    if (const SVGElement* element = correspondingElement())
+        return toSVGPathElement(element)->asPath();
+
+    return m_path->currentValue()->path();
 }
 
 float SVGPathElement::getTotalLength()
 {
     return getTotalLengthOfSVGPathByteStream(pathByteStream());
 }
 
 PassRefPtrWillBeRawPtr<SVGPointTearOff> SVGPathElement::getPointAtLength(float length)
 {
     FloatPoint point = getPointAtLengthOfSVGPathByteStream(pathByteStream(), length);
@@ skipping 47 matching lines @@
     return InsertionDone;
 }
 
 void SVGPathElement::removedFrom(ContainerNode* rootParent)
 {
     SVGGeometryElement::removedFrom(rootParent);
     invalidateMPathDependencies();
 }
 
 } // namespace blink