Add PlatformWindow/Event related code for Ozone X11.

ui/ozone/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/ui.gni")
 import("//ui/ozone/ozone.gni")
 import("//testing/test.gni")
 
 assert(use_ozone)
 
@@ skipping 30 matching lines @@
 if (ozone_platform_cast) {
   ozone_platforms += [ "cast" ]
   ozone_platform_deps += [ "platform/cast" ]
 }
 
 if (ozone_platform_wayland) {
   ozone_platforms += [ "wayland" ]
   ozone_platform_deps += [ "platform/wayland" ]
 }
 
+if (ozone_platform_x11) {
+  ozone_platforms += [ "x11" ]
+  ozone_platform_deps += [ "platform/x11" ]
+}
+
 platform_list_cc_file = "$target_gen_dir/platform_list.cc"
 platform_list_h_file = "$target_gen_dir/platform_list.h"
 platform_list_txt_file = "$target_gen_dir/platform_list.txt"
 constructor_list_cc_file = "$target_gen_dir/constructor_list.cc"
 
 config("vgem_map") {
   if (use_vgem_map) {
     defines = [ "USE_VGEM_MAP" ]
   }
 }
@@ skipping 148 matching lines @@
   sources = [
     "run_all_unittests.cc",
   ]
 
   deps = [
            "//base/test:test_support",
            "//testing/gtest",
            "//ui/gfx/geometry",
          ] + ozone_platform_test_deps
 }