CSS Custom Properties (Variables)

Source/core/css/resolver/CSSPropertyPriority.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CSSPropertyPriority_h
 #define CSSPropertyPriority_h
 
 #include "core/CSSPropertyNames.h"
 
 namespace blink {
 
 // The values of high priority properties affect the values of low priority
 // properties. For example, the value of the high priority property 'font-size'
 // decides the pixel value of low priority properties with 'em' units.
 
 enum CSSPropertyPriority {
+    ResolveVariables,
     HighPropertyPriority,
     LowPropertyPriority
 };
 
 template <CSSPropertyPriority priority>
 class CSSPropertyPriorityData {
 public:
     static inline CSSPropertyID first();
     static inline CSSPropertyID last();
     static inline bool propertyHasPriority(CSSPropertyID prop)
     {
         return first() <= prop && prop <= last();
     }
 };
 
 template<>
+inline CSSPropertyID CSSPropertyPriorityData<ResolveVariables>::first()
+{
+    static_assert(CSSPropertyVariable == lastCSSProperty, "CSSPropertyVariable should be the last property.");
+    return CSSPropertyVariable;
+}
+
+template<>
+inline CSSPropertyID CSSPropertyPriorityData<ResolveVariables>::last()
+{
+    return CSSPropertyVariable;
+}
+
+template<>
 inline CSSPropertyID CSSPropertyPriorityData<HighPropertyPriority>::first()
 {
     static_assert(CSSPropertyColor == firstCSSProperty, "CSSPropertyColor should be the first high priority property");
     return CSSPropertyColor;
 }
 
 template<>
 inline CSSPropertyID CSSPropertyPriorityData<HighPropertyPriority>::last()
 {
     static_assert(CSSPropertyZoom == CSSPropertyColor + 17, "CSSPropertyZoom should be the end of the high priority property range");
     static_assert(CSSPropertyTextRendering == CSSPropertyZoom - 1, "CSSPropertyTextRendering should be immediately before CSSPropertyZoom");
     return CSSPropertyZoom;
 }
 
 template<>
 inline CSSPropertyID CSSPropertyPriorityData<LowPropertyPriority>::first()
 {
     static_assert(CSSPropertyAlignContent == CSSPropertyZoom + 1, "CSSPropertyAlignContent should be the first low priority property");
     return CSSPropertyAlignContent;
 }
 
 template<>
 inline CSSPropertyID CSSPropertyPriorityData<LowPropertyPriority>::last()
 {
-    return static_cast<CSSPropertyID>(lastCSSProperty);
+    static_assert(lastCSSProperty - 1 < CSSPropertyVariable, "CSSPropertyVariable shouldn't be included in low priority properties.");
+    return static_cast<CSSPropertyID>(lastCSSProperty - 1);
 }
 
 } // namespace blink
 
 #endif // CSSPropertyPriority_h