Make EBorderStyle an enum class.

third_party/WebKit/Source/core/layout/LayoutThemeMac.mm

Index: third_party/WebKit/Source/core/layout/LayoutThemeMac.mm
diff --git a/third_party/WebKit/Source/core/layout/LayoutThemeMac.mm b/third_party/WebKit/Source/core/layout/LayoutThemeMac.mm
index 72a2a14b54a9205501ce9da81fd9388397ba7113..fd62e03fb72071b9794b5fa353d3b23976dc1547 100644
--- a/third_party/WebKit/Source/core/layout/LayoutThemeMac.mm
+++ b/third_party/WebKit/Source/core/layout/LayoutThemeMac.mm
@@ -881,13 +881,13 @@ void LayoutThemeMac::AdjustSearchFieldStyle(ComputedStyle& style) const {
   style.ResetBorder();
   const short border_width = kSearchFieldBorderWidth * style.EffectiveZoom();
   style.SetBorderLeftWidth(border_width);
-  style.SetBorderLeftStyle(kBorderStyleInset);
+  style.SetBorderLeftStyle(EBorderStyle::kInset);
   style.SetBorderRightWidth(border_width);
-  style.SetBorderRightStyle(kBorderStyleInset);
+  style.SetBorderRightStyle(EBorderStyle::kInset);
   style.SetBorderBottomWidth(border_width);
-  style.SetBorderBottomStyle(kBorderStyleInset);
+  style.SetBorderBottomStyle(EBorderStyle::kInset);
   style.SetBorderTopWidth(border_width);
-  style.SetBorderTopStyle(kBorderStyleInset);
+  style.SetBorderTopStyle(EBorderStyle::kInset);
 
   // Override height.
   style.SetHeight(Length(kAuto));