Make EUserSelect 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 2d3e107e091833e5fc70b53a95b1843792a871e0..6930521c248e1e2e1344d8c1c13dcf3b54698290 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.h
@@ -1988,12 +1988,12 @@ class CORE_EXPORT ComputedStyle : public ComputedStyleBase<ComputedStyle>,
   }
 
   // -webkit-user-select
-  static EUserSelect InitialUserSelect() { return SELECT_TEXT; }
+  static EUserSelect InitialUserSelect() { return EUserSelect::kText; }
   EUserSelect UserSelect() const {
     return static_cast<EUserSelect>(rare_inherited_data_->user_select_);
   }
   void SetUserSelect(EUserSelect s) {
-    SET_VAR(rare_inherited_data_, user_select_, s);
+    SET_VAR(rare_inherited_data_, user_select_, static_cast<unsigned>(s));
   }
 
   // caret-color