keycodes: Fix non-X11 build when use_xkbcommon=1

ui/events/keycodes/BUILD.gn

 # Copyright 2016 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/ui.gni")
 import("//ui/ozone/ozone.gni")
 
 source_set("xkb") {
   sources = [
     "keyboard_code_conversion_xkb.cc",
     "keyboard_code_conversion_xkb.h",
     "scoped_xkb.h",
     "xkb_keysym.h",
   ]
 
   deps = [
     "//base",
     "//ui/events:dom_keycode_converter",
   ]
+
+  if (use_xkbcommon) {
+    defines = [ "USE_XKBCOMMON" ]
+  }
 }
 
 if (use_x11 || ozone_platform_x11) {
   component("x11") {
     output_name = "keycodes_x11"
 
     sources = [
       "keyboard_code_conversion_x.cc",
       "keyboard_code_conversion_x.h",
       "keycodes_x_export.h",
       "keysym_to_unicode.cc",
       "keysym_to_unicode.h",
     ]
 
     defines = [ "KEYCODES_X_IMPLEMENTATION" ]
 
     deps = [
       ":xkb",
       "//base",
       "//ui/events:dom_keycode_converter",
       "//ui/gfx/x",
     ]
 
     configs += [ "//build/config/linux:x11" ]
   }
 }