[Variables] Enable get/setProperty and similar APIs from the CSSOM

third_party/WebKit/Source/build/scripts/templates/CSSPropertyMetadata.cpp.tmpl

 {% from 'macros.tmpl' import license %}
 {{license()}}
 
 #include "config.h"
 #include "core/css/CSSPropertyMetadata.h"
 
 #include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/BitArray.h"
 
 namespace blink {
 {% for flag, function_name in switches %}
 
 bool CSSPropertyMetadata::{{function_name}}(CSSPropertyID property)
 {
     switch(property) {
     case CSSPropertyInvalid:
         ASSERT_NOT_REACHED();
         return false;
     {% for property_id, property in properties.items() if property[flag] %}
     case {{property_id}}:
     {% endfor %}
         return true;
     default:
         return false;
     }
 }
 {% endfor %}
 
+// There is one more valid property ID than the total count of CSS properties
+// because of custom properties.
+static const int numValidPropertyIDs = numCSSProperties + 1;
+
 bool CSSPropertyMetadata::isEnabledProperty(CSSPropertyID unresolvedProperty)
 {
     CSSPropertyID property = resolveCSSPropertyID(unresolvedProperty);
-    static BitArray<numCSSProperties>* enabledProperties = 0;
+    static BitArray<numValidPropertyIDs>* enabledProperties = 0;
     if (!enabledProperties) {
-        enabledProperties = new BitArray<numCSSProperties>(true); // All bits sets to 1.
+        enabledProperties = new BitArray<numValidPropertyIDs>(true); // All bits sets to 1.
+        static_assert(CSSPropertyVariable == {{first_enum_value - 1}}, "CSSPropertyVariable should directly precede first_enum_value.");
+        if (!RuntimeEnabledFeatures::cssVariablesEnabled())
+            enabledProperties->clear(0);
         {% for property_id, property in properties.items() if property.runtime_flag %}
         if (!RuntimeEnabledFeatures::{{property.runtime_flag|lower_first}}Enabled())
-            enabledProperties->clear({{property_id}} - {{first_enum_value}});
+            enabledProperties->clear({{property_id}} - {{first_enum_value - 1}});
         {% endfor %}
         {% for property_id, property in properties.items() if property.is_internal %}
-        enabledProperties->clear({{property_id}} - {{first_enum_value}});
+        enabledProperties->clear({{property_id}} - {{first_enum_value - 1}});
         {% endfor %}
     }
-    return enabledProperties->get(property - {{first_enum_value}});
+    return enabledProperties->get(property - {{first_enum_value - 1}});
 }
 
 void CSSPropertyMetadata::filterEnabledCSSPropertiesIntoVector(const CSSPropertyID* properties, size_t propertyCount, Vector<CSSPropertyID>& outVector)
 {
     for (unsigned i = 0; i < propertyCount; i++) {
         CSSPropertyID property = properties[i];
         if (isEnabledProperty(property))
             outVector.append(property);
     }
 }
 
 } // namespace blink