Don't resolve rectangle as different unit if viewport is empty

Source/core/svg/SVGLengthContext.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * 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 91 matching lines @@
 }
 
 SVGLengthContext::SVGLengthContext(const SVGElement* context)
     : m_context(context)
 {
 }
 
 FloatRect SVGLengthContext::resolveRectangle(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const FloatRect& viewport, const SVGLength& x, const SVGLength& y, const SVGLength& width, const SVGLength& height)
 {
     ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
-    if (type != SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE && !viewport.isEmpty()) {
+    if (type != SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
         const FloatSize& viewportSize = viewport.size();
         return FloatRect(
             convertValueFromPercentageToUserUnits(x, viewportSize) + viewport.x(),
             convertValueFromPercentageToUserUnits(y, viewportSize) + viewport.y(),
             convertValueFromPercentageToUserUnits(width, viewportSize),
             convertValueFromPercentageToUserUnits(height, viewportSize));
     }
 
     SVGLengthContext lengthContext(context);
     return FloatRect(x.value(lengthContext), y.value(lengthContext), width.value(lengthContext), height.value(lengthContext));
@@ skipping 225 matching lines @@
 
     const SVGSVGElement& svg = toSVGSVGElement(*viewportElement);
     viewportSize = svg.currentViewBoxRect().size();
     if (viewportSize.isEmpty())
         viewportSize = svg.currentViewportSize();
 
     return true;
 }
 
 }