Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

ui/native_theme/native_theme_mac.mm

Index: ui/native_theme/native_theme_mac.mm
diff --git a/ui/native_theme/native_theme_mac.mm b/ui/native_theme/native_theme_mac.mm
index 1960780c25bb56abfa549dca114d35fdceec52aa..08a4cec5f9b212edbb6638d3ce34ac3153ebde7d 100644
--- a/ui/native_theme/native_theme_mac.mm
+++ b/ui/native_theme/native_theme_mac.mm
@@ -188,8 +188,8 @@ SkColor NativeThemeMac::GetSystemColor(ColorId color_id) const {
     case kColorId_MenuBackgroundColor:
       return kMenuPopupBackgroundColor;
     case kColorId_MenuSeparatorColor:
-      return base::mac::IsOS10_9() ? kMenuSeparatorColorMavericks
-                                   : kMenuSeparatorColor;
+      return base::mac::IsAtLeastOS10_10() ? kMenuSeparatorColor
+                                           : kMenuSeparatorColorMavericks;
     case kColorId_MenuBorderColor:
       return kMenuBorderColor;
 
@@ -250,10 +250,10 @@ void NativeThemeMac::PaintMenuPopupBackground(
     const MenuBackgroundExtraParams& menu_background) const {
   SkPaint paint;
   paint.setAntiAlias(true);
-  if (base::mac::IsOS10_9())
-    paint.setColor(kMenuPopupBackgroundColorMavericks);
-  else
+  if (base::mac::IsAtLeastOS10_10())
     paint.setColor(kMenuPopupBackgroundColor);
+  else
+    paint.setColor(kMenuPopupBackgroundColorMavericks);
   const SkScalar radius = SkIntToScalar(menu_background.corner_radius);
   SkRect rect = gfx::RectToSkRect(gfx::Rect(size));
   canvas->drawRoundRect(rect, radius, radius, paint);