libgtk2ui should only add the cups config if use_cups is true

chrome/browser/ui/libgtk2ui/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 assert(is_linux, "This file should only be referenced on Linux")
 
 import("//build/config/features.gni")
 
 component("libgtk2ui") {
   sources = [
@@ skipping 47 matching lines @@
   if (use_gconf) {
     sources += [
       "gconf_listener.cc",
       "gconf_listener.h",
     ]
   }
   defines = [ "LIBGTK2UI_IMPLEMENTATION" ]
 
   configs += [
     "//build/config/linux:gconf",
-    "//printing:cups",
   ]
 
+  if (use_cups) {
+    configs += [
+      "//printing:cups",
+    ]
+  }
+
   # GTK2 pulls pangoft2 as dependency, and pangoft2 depends on harfbuzz.
   # To avoid missing indirectly referenced harfbuzz symbols from pango,
   # some hack is required when bundled harfbuzz is used and component build is
   # disabled.
   # See crbug.com/462689 for details.
   all_dependent_configs = [ "//third_party/harfbuzz-ng:pangoft2_link_hack" ]
 
   # gn orders flags on a target before flags from configs. The default config
   # adds -Wall, and these flags have to be after -Wall -- so they need to come
   # from a config and can't be on the target directly.
@@ skipping 37 matching lines @@
     "//ui/events:events_base",
     "//ui/gfx",
     "//ui/gfx/x",
     "//ui/native_theme",
     "//ui/resources",
     "//ui/shell_dialogs",
     "//ui/strings",
     "//ui/views",
   ]
 }