Make EImageRendering 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 a817d9ae3b0dba345c70e7b4260985ce3a309867..f18341677fc0fb292a467dab9ea00088a085a800 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyleConstants.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyleConstants.h
@@ -317,12 +317,12 @@ enum TextOrientation {
 
 enum TextOverflow { kTextOverflowClip = 0, kTextOverflowEllipsis };
 
-enum EImageRendering {
-  kImageRenderingAuto,
-  kImageRenderingOptimizeSpeed,
-  kImageRenderingOptimizeQuality,
-  kImageRenderingOptimizeContrast,
-  kImageRenderingPixelated
+enum class EImageRendering {
+  kAuto,
+  kOptimizeSpeed,
+  kOptimizeQuality,
+  kOptimizeContrast,
+  kPixelated
 };
 
 enum RubyPosition { kRubyPositionBefore, kRubyPositionAfter };