MacViews: Overlay Scrollbars with Show/Hide Animations

ui/base/test/scoped_preferred_scroller_style_mac.h

Index: ui/base/test/scoped_preferred_scroller_style_mac.h
diff --git a/ui/base/test/scoped_preferred_scroller_style_legacy_mac.h b/ui/base/test/scoped_preferred_scroller_style_mac.h
similarity index 59%
rename from ui/base/test/scoped_preferred_scroller_style_legacy_mac.h
rename to ui/base/test/scoped_preferred_scroller_style_mac.h
index 99b0028db8fccad760749cb072caa12773280947..616fc965a4c63cd8947fee62eb97eebedae36f46 100644
--- a/ui/base/test/scoped_preferred_scroller_style_legacy_mac.h
+++ b/ui/base/test/scoped_preferred_scroller_style_mac.h
@@ -17,17 +17,21 @@ class ScopedObjCClassSwizzler;
 namespace ui {
 namespace test {
 
-// Overrides system setting for scrollbar style with NSScrollerStyleLegacy,
-// which means "always show scrollbars".
-class ScopedPreferredScrollerStyleLegacy {
+// Overrides system setting for scrollbar style with NSScrollerOverlay if we
+// want the scrollbar to overlay. Otherwise, override with
+// NSScrollerStyleLegacy which means "always show scrollbars".
+class ScopedPreferredScrollerStyle {
  public:
-  ScopedPreferredScrollerStyleLegacy();
-  ~ScopedPreferredScrollerStyleLegacy();
+  ScopedPreferredScrollerStyle(bool overlay);

[tapted, 2016/02/19 06:56:37]

nit: explicit

[aside: It's also common to use an enum like
ScopedPreferredScrollerStyle::OVERLAY/LEGACY rather than a bool (but "legacy"
isn't very descriptive anyway -- it's basically "not overlay" -- so I'm
indifferent. Plus it would be silly to provide our own enum when Cocoa provides
one we don't want to expose so this can be included in C++ files)]

[spqchan, 2016/02/19 19:35:32]

Done.

+  ~ScopedPreferredScrollerStyle();
 
  private:
   scoped_ptr<base::mac::ScopedObjCClassSwizzler> swizzler_;
 
-  DISALLOW_COPY_AND_ASSIGN(ScopedPreferredScrollerStyleLegacy);
+  // True if the scrollbar style should overlay.
+  bool overlay_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedPreferredScrollerStyle);
 };
 
 }  // namespace test