Make TextUnderlinePosition an enum class.

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

Index: third_party/WebKit/Source/core/style/ComputedStyleConstants.h
diff --git a/third_party/WebKit/Source/core/style/ComputedStyleConstants.h b/third_party/WebKit/Source/core/style/ComputedStyleConstants.h
index 5bbe48c46871ec7025a58eec288dd88be97ea7d5..85366807b6c363b502eba5d630b1a5c10f6a8d9c 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyleConstants.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyleConstants.h
@@ -248,10 +248,10 @@ inline TextDecorationSkip& operator|=(TextDecorationSkip& a,
   return a = a | b;
 }
 
-enum TextUnderlinePosition {
+enum class TextUnderlinePosition {
   // FIXME: Implement support for 'under left' and 'under right' values.
-  kTextUnderlinePositionAuto,
-  kTextUnderlinePositionUnder
+  kAuto,
+  kUnder
 };
 
 enum ETransformStyle3D { kTransformStyle3DFlat, kTransformStyle3DPreserve3D };