Make RubyPosition an enum class.

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

Index: third_party/WebKit/Source/core/css/CSSPrimitiveValueMappings.h
diff --git a/third_party/WebKit/Source/core/css/CSSPrimitiveValueMappings.h b/third_party/WebKit/Source/core/css/CSSPrimitiveValueMappings.h
index 6c07e882094a867bbe045319a66bc9cf7dfbe742..6187bd05ea7a498613426e64652c380c31c643f6 100644
--- a/third_party/WebKit/Source/core/css/CSSPrimitiveValueMappings.h
+++ b/third_party/WebKit/Source/core/css/CSSPrimitiveValueMappings.h
@@ -1580,10 +1580,10 @@ template <>
 inline CSSIdentifierValue::CSSIdentifierValue(RubyPosition position)
     : CSSValue(kIdentifierClass) {
   switch (position) {
-    case kRubyPositionBefore:
+    case RubyPosition::kBefore:
       value_id_ = CSSValueBefore;
       break;
-    case kRubyPositionAfter:
+    case RubyPosition::kAfter:
       value_id_ = CSSValueAfter;
       break;
   }
@@ -1593,15 +1593,15 @@ template <>
 inline RubyPosition CSSIdentifierValue::ConvertTo() const {
   switch (value_id_) {
     case CSSValueBefore:
-      return kRubyPositionBefore;
+      return RubyPosition::kBefore;
     case CSSValueAfter:
-      return kRubyPositionAfter;
+      return RubyPosition::kAfter;
     default:
       break;
   }
 
   NOTREACHED();
-  return kRubyPositionBefore;
+  return RubyPosition::kBefore;
 }
 
 template <>