Update error-handling for fe*Lighting and feTurbulence

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

 /*
  * Copyright (C) 2005 Oliver Hunt <ojh16@student.canterbury.ac.nz>
  *
  * 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 108 matching lines @@
     primitiveAttributeChanged(attrName);
 }
 
 PassRefPtrWillBeRawPtr<FilterEffect> SVGFEDiffuseLightingElement::build(SVGFilterBuilder* filterBuilder, Filter* filter)
 {
     FilterEffect* input1 = filterBuilder->getEffectById(AtomicString(m_in1->currentValue()->value()));
 
     if (!input1)
         return nullptr;
 
-    SVGFELightElement* lightNode = SVGFELightElement::findLightElement(*this);
-    if (!lightNode)
-        return nullptr;
-
     LayoutObject* layoutObject = this->layoutObject();
     if (!layoutObject)
         return nullptr;
 
     ASSERT(layoutObject->style());
     Color color = layoutObject->style()->svgStyle().lightingColor();
 
-    RefPtr<LightSource> lightSource = lightNode->lightSource(filter);
-    RefPtrWillBeRawPtr<FilterEffect> effect = FEDiffuseLighting::create(filter, color, m_surfaceScale->currentValue()->value(), m_diffuseConstant->currentValue()->value(),
+    const SVGFELightElement* lightNode = SVGFELightElement::findLightElement(*this);
+    RefPtr<LightSource> lightSource = lightNode ? lightNode->lightSource(filter) : nullptr;
+
+    RefPtrWillBeRawPtr<FilterEffect> effect = FEDiffuseLighting::create(filter,
+        color,
+        m_surfaceScale->currentValue()->value(),
+        m_diffuseConstant->currentValue()->value(),
         lightSource.release());
     effect->inputEffects().append(input1);
     return effect.release();
 }
 
 } // namespace blink