Resolve percentage in <use> against the instance's viewport element

third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Google, Inc.
  *
  * 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.
  *
@@ skipping 72 matching lines @@
     SVGUseElement* useElement = nullptr;
     if (isSVGUseElement(*element)) {
         useElement = toSVGUseElement(element);
     } else if (isSVGGElement(*element) && toSVGGElement(element)->inUseShadowTree()) {
         SVGElement* correspondingElement = element->correspondingElement();
         if (isSVGUseElement(correspondingElement))
             useElement = toSVGUseElement(correspondingElement);
     }
 
     if (useElement) {
-        SVGLengthContext lengthContext(useElement);
+        SVGLengthContext lengthContext(element);
         FloatSize translation(
             useElement->x()->currentValue()->value(lengthContext),
             useElement->y()->currentValue()->value(lengthContext));
         // TODO(fs): Signal this on style update instead. (Since these are
         // suppose to be presentation attributes now, this does feel a bit
         // broken...)
         if (translation != m_additionalTranslation)
             setNeedsTransformUpdate();
         m_additionalTranslation = translation;
     }
 
     if (!m_needsTransformUpdate)
         return SVGTransformChange::None;
 
     SVGTransformChangeDetector changeDetector(m_localTransform);
     m_localTransform = element->calculateAnimatedLocalTransform();
     m_localTransform.translate(m_additionalTranslation.width(), m_additionalTranslation.height());
     m_needsTransformUpdate = false;
     return changeDetector.computeChange(m_localTransform);
 }
 
 } // namespace blink