Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

ui/views/controls/menu/menu_config_mac.mm

Index: ui/views/controls/menu/menu_config_mac.mm
diff --git a/ui/views/controls/menu/menu_config_mac.mm b/ui/views/controls/menu/menu_config_mac.mm
index fc66f894436da1b5049280ff7dcbb2e07a8db186..f28b62a081ef739ce8af83f32e31be8a430c31ef 100644
--- a/ui/views/controls/menu/menu_config_mac.mm
+++ b/ui/views/controls/menu/menu_config_mac.mm
@@ -31,8 +31,9 @@ void MenuConfig::Init() {
   separator_height = 13;
   separator_upper_height = 7;
   separator_lower_height = 6;
-  separator_thickness = base::mac::IsOS10_9() ? kMenuSeparatorHeightMavericks
-                                              : kMenuSeparatorHeight;
+  separator_thickness = base::mac::IsAtLeastOS10_10()
+                            ? kMenuSeparatorHeight
+                            : kMenuSeparatorHeightMavericks;
   align_arrow_and_shortcut = true;
   icons_in_label = true;
   check_selected_combobox_item = true;