Reorder the AnimatedPropertyType enumeration

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * 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
@@ skipping 685 matching lines @@
             { text_anchorAttr, AnimatedString },
             { text_decorationAttr, AnimatedString },
             { text_renderingAttr, AnimatedString },
             { vector_effectAttr, AnimatedString },
             { visibilityAttr, AnimatedString },
             { word_spacingAttr, AnimatedLength },
         };
         for (size_t i = 0; i < WTF_ARRAY_LENGTH(attrToTypes); i++)
             cssPropertyMap.set(attrToTypes[i].attr, attrToTypes[i].propType);
     }
-
-    if (cssPropertyMap.contains(attributeName))
-        return cssPropertyMap.get(attributeName);
-
-    return AnimatedUnknown;
+    // If the attribute is not present in the map, this will return the "empty
+    // value" per HashTraits - which is AnimatedUnknown.
+    return cssPropertyMap.get(attributeName);

[pdr., 2016/08/29 00:07:09]

In addition to this comment, can you enforce it with a DCHECK to prevent against
bad refactorings of the enum or hashtraits?

Possibly the following here or up in the cssPropertyMap initialization block
above:
DCHECK(HashTraits<AnimatedPropertyType>::emptyValue() == AnimatedUnknown);

 }
 
 void SVGElement::addToPropertyMap(SVGAnimatedPropertyBase* property)
 {
     m_attributeToPropertyMap.set(property->attributeName(), property);
 }
 
 SVGAnimatedPropertyBase* SVGElement::propertyFromAttribute(const QualifiedName& attributeName) const
 {
     AttributeToPropertyMap::const_iterator it = m_attributeToPropertyMap.find<SVGAttributeHashTranslator>(attributeName);
@@ skipping 488 matching lines @@
     Element::trace(visitor);
 }
 
 const AtomicString& SVGElement::eventParameterName()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, evtString, ("evt"));
     return evtString;
 }
 
 } // namespace blink