Resubmission of sashab's patch: Make CSSComputedStyledeclaration::getPropertyCSSValue return const

third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Research In Motion Limited. 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 240 matching lines @@
     else
         changed = propertySet().removeProperty(propertyID, &result);
 
     didMutate(changed ? PropertyChanged : NoChanges);
 
     if (changed)
         mutationScope.enqueueMutationRecord();
     return result;
 }
 
-CSSValue* AbstractPropertySetCSSStyleDeclaration::getPropertyCSSValueInternal(CSSPropertyID propertyID)
+const CSSValue* AbstractPropertySetCSSStyleDeclaration::getPropertyCSSValueInternal(CSSPropertyID propertyID)
 {
     return propertySet().getPropertyCSSValue(propertyID);
 }
 
 String AbstractPropertySetCSSStyleDeclaration::getPropertyValueInternal(CSSPropertyID propertyID)
 {
     return propertySet().getPropertyValue(propertyID);
 }
 
 void AbstractPropertySetCSSStyleDeclaration::setPropertyInternal(CSSPropertyID unresolvedProperty, const String& customPropertyName, const String& value, bool important, ExceptionState&)
@@ skipping 97 matching lines @@
     return m_parentElement ? &m_parentElement->document().elementSheet() : nullptr;
 }
 
 DEFINE_TRACE(InlineCSSStyleDeclaration)
 {
     visitor->trace(m_parentElement);
     AbstractPropertySetCSSStyleDeclaration::trace(visitor);
 }
 
 } // namespace blink