Fix gtk3 build

remoting/test/BUILD.gn

 # Copyright 2015 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("//remoting/remoting_enable.gni")
 
 static_library("test_support") {
   testonly = true
 
   sources = [
@@ skipping 178 matching lines @@
     sources = [
       "it2me_standalone_host_main.cc",
     ]
 
     deps = [
       ":it2me_standalone_host",
       "//build/win:default_exe_manifest",
     ]
 
     if (is_desktop_linux) {
-      deps += [ "//build/config/linux/gtk2" ]
+      if (use_gtk3) {
+        deps += [ "//build/config/linux/gtk3" ]
+      } else {
+        deps += [ "//build/config/linux/gtk2" ]
+      }
     }
   }
 }
 
 source_set("unit_tests") {
   testonly = true
 
   sources = [
     "access_token_fetcher_unittest.cc",
     "app_remoting_report_issue_request_unittest.cc",
@@ skipping 10 matching lines @@
     ":ar_test_driver_common",
     ":test_support",
     "//base",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/libyuv",
     "//third_party/webrtc/modules/desktop_capture",
   ]
 }