Make the ENABLE_APP_LIST build flag work on Linux

ui/app_list/app_list_constants.cc

Index: ui/app_list/app_list_constants.cc
diff --git a/ui/app_list/app_list_constants.cc b/ui/app_list/app_list_constants.cc
index 84706bd88634e27e750b50a938b60a5bf62bd06f..47d73c43051ad7fa5457012bd9e8cd902c2af274 100644
--- a/ui/app_list/app_list_constants.cc
+++ b/ui/app_list/app_list_constants.cc
@@ -25,9 +25,6 @@ const SkColor kLabelBackgroundColor = kContentsBackgroundColor;
 const SkColor kTopSeparatorColor = SkColorSetRGB(0xC0, 0xC0, 0xC0);
 const SkColor kBottomSeparatorColor = SkColorSetRGB(0xC0, 0xC0, 0xC0);
 
-// The color of the separator used inside dialogs in the app list.
-const SkColor kDialogSeparatorColor = SkColorSetRGB(0xD1, 0xD1, 0xD1);
-
 // The mouse hover colour (3% black).
 const SkColor kHighlightedColor = SkColorSetARGB(8, 0, 0, 0);
 // The keyboard select colour (6% black).