Split out CSSPrimitiveValue's PropertyID into CSSCustomIdentValue

third_party/WebKit/Source/core/css/CSSCustomIdentValue.h

Index: third_party/WebKit/Source/core/css/CSSCustomIdentValue.h
diff --git a/third_party/WebKit/Source/core/css/CSSCustomIdentValue.h b/third_party/WebKit/Source/core/css/CSSCustomIdentValue.h
index 4eea95183f5fcfc83f799f3227ac35e413109928..df4cce19cd991a817b1d9a6fbf61bbc31c4e83c4 100644
--- a/third_party/WebKit/Source/core/css/CSSCustomIdentValue.h
+++ b/third_party/WebKit/Source/core/css/CSSCustomIdentValue.h
@@ -5,6 +5,7 @@
 #ifndef CSSCustomIdentValue_h
 #define CSSCustomIdentValue_h
 
+#include "core/CSSPropertyNames.h"
 #include "core/css/CSSValue.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
@@ -18,21 +19,32 @@ public:
         return adoptRefWillBeNoop(new CSSCustomIdentValue(str));
     }
 
-    String value() const { return m_string; }
+    // TODO(sashab, timloh): Remove this and lazily parse the CSSPropertyID in isKnownPropertyID().
+    static PassRefPtrWillBeRawPtr<CSSCustomIdentValue> create(CSSPropertyID id)
+    {
+        return adoptRefWillBeNoop(new CSSCustomIdentValue(id));
+    }
+
+    String value() const { ASSERT(!isKnownPropertyID()); return m_string; }
+    bool isKnownPropertyID() const { return m_propertyId != CSSPropertyInvalid; }
+    CSSPropertyID valueAsPropertyID() const { ASSERT(isKnownPropertyID()); return m_propertyId; }
 
     String customCSSText() const;
 
     bool equals(const CSSCustomIdentValue& other) const
     {
-        return m_string == other.m_string;
+        return isKnownPropertyID() ? m_propertyId == other.m_propertyId : m_string == other.m_string;
     }
 
     DECLARE_TRACE_AFTER_DISPATCH();
 
 private:
     CSSCustomIdentValue(const String&);
+    CSSCustomIdentValue(CSSPropertyID);
 
+    // TODO(sashab): Change this to an AtomicString.
     String m_string;
+    CSSPropertyID m_propertyId;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSCustomIdentValue, isCustomIdentValue());