Hook up more GN toolkit and UI-based flags.

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/sysroot.gni")
 
 config("sdk") {
   if (sysroot != "") {
     cflags = [ "--sysroot=" + sysroot ]
@@ skipping 27 matching lines @@
 }
 
 pkg_config("glib") {
   packages = [ "glib-2.0", "gmodule-2.0", "gobject-2.0", "gthread-2.0" ]
 }
 
 pkg_config("gtk") {
   # Gtk requires gmodule, but it does not list it as a dependency in some
   # misconfigured systems.
   packages = [ "gmodule-2.0", "gtk+-2.0", "gthread-2.0" ]
-  defines = [ "TOOLKIT_GTK" ]
 }
 
 pkg_config("pangocairo") {
   packages = [ "pangocairo" ]
 }
 
 pkg_config("udev") {
   packages = [ "libudev" ]
 }
 
 config("x11") {
   # Don't bother running pkg-config for these X related libraries since it just
   # returns the same libs, and forking pkg-config is slow.
-  defines = [ "USE_X11" ]
   libs = [
     "X11",
     "Xcomposite",
     "Xcursor",
     "Xdamage",
     "Xext",
     "Xfixes",
     "Xi",
     "Xrender",
     "Xss",
     "Xtst",
   ]
 }