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

Source/platform/scroll/ScrollbarThemeMacCommon.h

Index: Source/platform/scroll/ScrollbarThemeMacCommon.h
diff --git a/Source/platform/scroll/ScrollbarThemeMacCommon.h b/Source/platform/scroll/ScrollbarThemeMacCommon.h
index c3e7fde10d5d82dd941b9803a57b43aa0fc7d26b..8de1c6bb3f965b8867ac1f85213267b24e4da57e 100644
--- a/Source/platform/scroll/ScrollbarThemeMacCommon.h
+++ b/Source/platform/scroll/ScrollbarThemeMacCommon.h
@@ -38,10 +38,9 @@ class Pattern;
 class PLATFORM_EXPORT ScrollbarThemeMacCommon : public ScrollbarTheme {
 public:
     ~ScrollbarThemeMacCommon() override;
-

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

nit. don't delete that line

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

Done.

     void registerScrollbar(ScrollbarThemeClient*) override;
     void unregisterScrollbar(ScrollbarThemeClient*) override;
-    void preferencesChanged(float initialButtonDelay, float autoscrollButtonDelay, NSScrollerStyle preferredScrollerStyle, bool redraw, bool scrollAnimationEnabled, const std::string& buttonPlacement);
+    void preferencesChanged(float initialButtonDelay, float autoscrollButtonDelay, NSScrollerStyle preferredScrollerStyle, bool redraw, bool scrollAnimationEnabled, ScrollbarButtonsPlacement buttonPlacement);

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

same here (and everywhere), drop buttonPlacement

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

Done.

 
     bool supportsControlTints() const override { return true; }
 
@@ -62,7 +61,7 @@ protected:
     bool shouldDragDocumentInsteadOfThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) override;
     int scrollbarPartToHIPressedState(ScrollbarPart);
 
-    virtual void updateButtonPlacement(const std::string& buttonPlacement) {}
+    virtual void updateButtonPlacement(ScrollbarButtonsPlacement buttonPlacement) {}
 
     void paintGivenTickmarks(SkCanvas*, ScrollbarThemeClient*, const IntRect&, const Vector<IntRect>&);