Make ETextModify an enum class.

third_party/WebKit/Source/core/style/ComputedStyle.h

Index: third_party/WebKit/Source/core/style/ComputedStyle.h
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.h b/third_party/WebKit/Source/core/style/ComputedStyle.h
index 74f2435d204fad85f976a3cbe27f5e45a72ba15d..28b6c2c2747a563a6bdc248115482c6f141762bd 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.h
@@ -1996,12 +1996,12 @@ class CORE_EXPORT ComputedStyle : public ComputedStyleBase,
   }
 
   // -webkit-user-modify
-  static EUserModify InitialUserModify() { return READ_ONLY; }
+  static EUserModify InitialUserModify() { return EUserModify::kReadOnly; }
   EUserModify UserModify() const {
     return static_cast<EUserModify>(rare_inherited_data_->user_modify_);
   }
   void SetUserModify(EUserModify u) {
-    SET_VAR(rare_inherited_data_, user_modify_, u);
+    SET_VAR(rare_inherited_data_, user_modify_, static_cast<unsigned>(u));
   }
 
   // -webkit-user-select