Pass scroll bar placement as an enum instead of std::string

public/web/mac/WebScrollbarTheme.h

Index: public/web/mac/WebScrollbarTheme.h
diff --git a/public/web/mac/WebScrollbarTheme.h b/public/web/mac/WebScrollbarTheme.h
index 4ba409d6c4f709b23088c4287a2feb9bfc88e3fd..34d9adb883e83aaaabb34f3fbf92acef2b000097 100644
--- a/public/web/mac/WebScrollbarTheme.h
+++ b/public/web/mac/WebScrollbarTheme.h
@@ -32,8 +32,7 @@
 #define WebScrollbarTheme_h
 
 #include "public/platform/WebCommon.h"
-
-#include <string>
+#include "public/platform/mac/MacScrollTypes.h"
 
 namespace blink {
 
@@ -58,7 +57,7 @@ public:
     BLINK_EXPORT static void updateScrollbarsWithNSDefaults(
         float initialButtonDelay, float autoscrollButtonDelay,
         ScrollerStyle preferredScrollerStyle, bool redraw,
-        bool scrollAnimationEnabled, const std::string& buttonPlacement);
+        bool scrollAnimationEnabled, ScrollbarButtonsPlacement buttonPlacement);

[jochen (gone - plz use gerrit), 2015/07/22 09:52:49]

now the name "buttonPlacement" doesn't add any value, just omit it.

[Greg K, 2015/07/22 19:41:55]

Done.

 };
 
 } // namespace blink