Clean up GTK3 build flags.

remoting/host/it2me/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.
 
 import("//build/config/features.gni")
 import("//remoting/remoting_enable.gni")
 import("//remoting/remoting_locales.gni")
 import("//remoting/remoting_version.gni")
 
 if (is_win) {
@@ skipping 39 matching lines @@
     "//remoting/signaling",
   ]
 
   if (is_desktop_linux) {
     # 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" ]
-
-    if (use_gtk3) {
-      deps += [ "//build/config/linux/gtk3" ]
-    } else {
-      deps += [ "//build/config/linux/gtk2" ]
-    }
+    deps += [ "//build/config/linux/gtk" ]
   }
 }
 
 if (!is_chromeos && enable_remoting_host) {
   if (is_win) {
     executable("remote_assistance_host") {
       configs += [ "//build/config/compiler:wexit_time_destructors" ]
 
       deps = [
         "//base/allocator",
@@ skipping 150 matching lines @@
         if (icu_use_data_file) {
           deps += [ ":remote_assistance_host_resources" ]
         }
       }
 
       if (enable_webrtc) {
         deps += [ "//third_party/libjingle/webrtc:libjingle_webrtc" ]
       }
 
       if (is_desktop_linux) {
-        if (use_gtk3) {
-          deps += [ "//build/config/linux/gtk3" ]
-        } else {
-          deps += [ "//build/config/linux/gtk2" ]
-        }
+        deps += [ "//build/config/linux/gtk" ]
       }
     }
   }
 }