MacViews: Implement Full Keyboard Access.

ui/views/controls/button/image_button.h

Index: ui/views/controls/button/image_button.h
diff --git a/ui/views/controls/button/image_button.h b/ui/views/controls/button/image_button.h
index 79e84d7d3e1a16682433ef83c118035ecbb10be1..9131ae25aaa7a77ccd41f24ba014913af266cd35 100644
--- a/ui/views/controls/button/image_button.h
+++ b/ui/views/controls/button/image_button.h
@@ -20,9 +20,8 @@ class Painter;
 // An image button.
 
 // Note that this type of button is not focusable by default and will not be
-// part of the focus chain.  Call SetFocusBehavior(FocusBehavior::ALWAYS) to
-// make it part of the focus chain.
-
+// part of the focus chain, unless in accessibility mode. Call
+// Button::ConfigureDefaultFocus() to make it part of the focus chain.
 class VIEWS_EXPORT ImageButton : public CustomButton {
  public:
   static const char kViewClassName[];