Replace hasAttribute with the check for actual value

Source/core/rendering/svg/RenderSVGViewportContainer.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.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 78 matching lines @@
 
         // Spec (<use> on <symbol>): This generated 'svg' will always have explicit values for attributes width and height.
         // If attributes width and/or height are provided on the 'use' element, then these attributes
         // will be transferred to the generated 'svg'. If attributes width and/or height are not specified,
         // the generated 'svg' element will use values of 100% for these attributes.
 
         // Spec (<use> on <svg>): If attributes width and/or height are provided on the 'use' element, then these
         // values will override the corresponding attributes on the 'svg' in the generated tree.
 
         SVGLengthContext lengthContext(element);
-        if (useElement->hasAttribute(SVGNames::widthAttr))
+        if (useElement->width().value(lengthContext) > 0)
             m_viewport.setWidth(useElement->width().value(lengthContext));
         else if (isSymbolElement && svg->hasAttribute(SVGNames::widthAttr)) {
             SVGLength containerWidth(LengthModeWidth, "100%");
             m_viewport.setWidth(containerWidth.value(lengthContext));
         }
 
-        if (useElement->hasAttribute(SVGNames::heightAttr))
+        if (useElement->height().value(lengthContext) > 0)
             m_viewport.setHeight(useElement->height().value(lengthContext));
         else if (isSymbolElement && svg->hasAttribute(SVGNames::heightAttr)) {
             SVGLength containerHeight(LengthModeHeight, "100%");
             m_viewport.setHeight(containerHeight.value(lengthContext));
         }
     }
 
     if (oldViewport != m_viewport) {
         setNeedsBoundariesUpdate();
         setNeedsTransformUpdate();
@@ skipping 35 matching lines @@
     // An empty viewBox disables rendering.
     if (node()->hasTagName(SVGNames::svgTag)) {
         if (toSVGSVGElement(node())->hasEmptyViewBox())
             return;
     }
 
     RenderSVGContainer::paint(paintInfo, paintOffset);
 }
 
 }