aura: Remove WindowTreeHost::PostNativeEvent().

ui/aura/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")
 
 component("aura") {
   sources = [
     "client/aura_constants.cc",
     "client/aura_constants.h",
@@ skipping 157 matching lines @@
     "test/test_window_tree_client.h",
     "test/test_windows.cc",
     "test/test_windows.h",
     "test/test_window_delegate.cc",
     "test/test_window_delegate.h",
     "test/ui_controls_factory_aura.h",
     "test/window_event_dispatcher_test_api.cc",
     "test/window_event_dispatcher_test_api.h",
     "test/window_test_api.cc",
     "test/window_test_api.h",
+    "test/x11_event_sender.cc",
+    "test/x11_event_sender.h",
   ]
 
   public_deps = [
     ":aura",
   ]
   deps = [
     "//skia",
     "//testing/gtest",
     "//ui/base:test_support",
     "//ui/compositor:test_support",
@@ skipping 112 matching lines @@
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 
   if (is_linux) {
     deps += [
       "//third_party/mesa",
     ]
   }
 }