Make EBorderStyle an enum class.

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

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 27 matching lines @@
   OutlineValue() : offset_(0) {}
 
   bool operator==(const OutlineValue& o) const {
     return BorderValue::operator==(o) && offset_ == o.offset_ &&
            is_auto_ == o.is_auto_;
   }
 
   bool operator!=(const OutlineValue& o) const { return !(*this == o); }
 
   bool VisuallyEqual(const OutlineValue& o) const {
-    if (style_ == kBorderStyleNone && o.style_ == kBorderStyleNone)
+    if (style_ == static_cast<unsigned>(EBorderStyle::kNone) &&
+        o.style_ == static_cast<unsigned>(EBorderStyle::kNone))
       return true;
     return *this == o;
   }
 
   int Offset() const { return offset_; }
   void SetOffset(int offset) { offset_ = offset; }
 
  private:
   int offset_;
 };
 
 }  // namespace blink
 
 #endif  // OutlineValue_h