Add GN interactive UI tests.

build/config/linux/BUILD.gn

 # Copyright (c) 2013 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/linux/pkg_config.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 import("//tools/generate_library_loader/generate_library_loader.gni")
 
@@ skipping 100 matching lines @@
 }
 
 config("libcap") {
   libs = [ "cap" ]
 }
 
 config("xi") {
   libs = [ "Xi" ]
 }
 
+config("xtst") {
+  libs = [ "Xtst" ]
+}
+
 config("libresolv") {
   libs = [ "resolv" ]
 }
 
 # CrOS doesn't install GTK, gconf or any gnome packages.
 if (!is_chromeos) {
   # These packages should _only_ be expected when building for a target.
   # If these extra checks are not run, gconf is required when building host
   # tools for a CrOS build.
   if (current_toolchain == default_toolchain) {
@@ skipping 87 matching lines @@
 
   functions = gypi_values.libudev_functions
 }
 
 group("udev") {
   deps = [
     ":udev0_loader",
     ":udev1_loader",
   ]
 }