Avoid ASSERT_NOT_REACHED in blink::floatValueForLength.

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 158 matching lines @@
 }
 
 float SVGLengthContext::valueForLength(const Length& length, const ComputedStyle& style, float dimension)
 {
     return valueForLength(length, style.effectiveZoom(), dimension);
 }
 
 float SVGLengthContext::valueForLength(const Length& length, float zoom, float dimension)
 {
     ASSERT(zoom != 0);
+    // isIntrinsic can occur for 'width' and 'height', but has no
+    // real meaning for svg.
+    if (length.isIntrinsic())
+        return 0;
     return floatValueForLength(length, dimension * zoom) / zoom;
 }
 
 float SVGLengthContext::convertValueToUserUnits(float value, SVGLengthMode mode, SVGLengthType fromUnit) const
 {
     float userUnits = value;
     switch (fromUnit) {
     case LengthTypeUnknown:
         return 0;
     case LengthTypePX:
@@ skipping 152 matching lines @@
 
     const SVGSVGElement& svg = toSVGSVGElement(*viewportElement);
     viewportSize = svg.currentViewBoxRect().size();
     if (viewportSize.isEmpty())
         viewportSize = svg.currentViewportSize();
 
     return true;
 }
 
 }