Don't unconditionally generate a layout object for SVG <stop> elements.

third_party/WebKit/Source/core/svg/SVGStopElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 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,
@@ skipping 38 matching lines @@
   }
 
   SVGElement::svgAttributeChanged(attrName);
 }
 
 LayoutObject* SVGStopElement::createLayoutObject(const ComputedStyle&) {
   return new LayoutSVGGradientStop(this);
 }
 
 bool SVGStopElement::layoutObjectIsNeeded(const ComputedStyle&) {
-  return true;
+  return isValid() && hasSVGParent();
 }
 
 Color SVGStopElement::stopColorIncludingOpacity() const {
   const ComputedStyle* style =
       layoutObject() ? layoutObject()->style() : nullptr;
   // FIXME: This check for null style exists to address Bug WK 90814, a rare
   // crash condition in which the layoutObject or style is null. This entire
   // class is scheduled for removal (Bug WK 86941) and we will tolerate this
   // null check until then.
   if (!style)
     return Color(Color::transparent);  // Transparent black.
 
   const SVGComputedStyle& svgStyle = style->svgStyle();
   return svgStyle.stopColor().combineWithAlpha(svgStyle.stopOpacity());
 }
 
 }  // namespace blink