Fix SVG animations which check viewBox attribute

Source/core/svg/SVGViewSpec.h

 /*
  * Copyright (C) 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 59 matching lines @@
     bool parseViewSpecInternal(const CharType* ptr, const CharType* end);
 
     RawPtrWillBeMember<SVGSVGElement> m_contextElement;
     RefPtrWillBeMember<SVGAnimatedTransformList> m_transform;
     String m_viewTargetString;
 };
 
 template <typename T>
 void SVGViewSpec::inheritViewAttributesFromElement(T* inheritFromElement)
 {
-    if (inheritFromElement->hasAttribute(SVGNames::viewBoxAttr))
+    if (!inheritFromElement->hasEmptyViewBox())
         viewBox()->baseValue()->setValue(inheritFromElement->viewBox()->currentValue()->value());

[fs, 2015/04/22 10:56:51]

This will just snapshot the value, which likely mean that viewBox animations
combined with fragment view-specs won't work great. That seems to be a
pre-existing condition though, so the not the fault of this CL.

 
     if (inheritFromElement->hasAttribute(SVGNames::preserveAspectRatioAttr)) {
         preserveAspectRatio()->baseValue()->setAlign(inheritFromElement->preserveAspectRatio()->currentValue()->align());
         preserveAspectRatio()->baseValue()->setMeetOrSlice(inheritFromElement->preserveAspectRatio()->currentValue()->meetOrSlice());
     }
 
     if (inheritFromElement->hasAttribute(SVGNames::zoomAndPanAttr))
         setZoomAndPan(inheritFromElement->zoomAndPan());
 }
 
 } // namespace blink
 
 #endif // SVGViewSpec_h