Move mus::InputEventHandler implementation and tests from PlatformWindowMus to NativeWidgetMus

ui/views/mus/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/features.gni")
 import("//build/config/ui.gni")
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/mojo_application_manifest.gni")
 import("//testing/test.gni")
 import("//tools/grit/repack.gni")
@@ skipping 156 matching lines @@
 
   configs += [ "//build/config:precompiled_headers" ]
 
   # TODO(sky): add more files.
   sources = [
     "../view_targeter_unittest.cc",
     "../widget/native_widget_unittest.cc",
     "../widget/widget_unittest.cc",
     "display_list_unittest.cc",
     "native_widget_mus_unittest.cc",
-    "platform_window_mus_unittest.cc",
     "run_all_unittests_mus.cc",
     "screen_mus_unittest.cc",
     "window_manager_connection_unittest.cc",
   ]
 
   deps = [
     ":mus",
     ":test_support",
     "//base",
     "//base:i18n",
@@ skipping 116 matching lines @@
 }
 
 group("for_component") {
   public_deps = [
     ":mus",
   ]
   deps = [
     "//mojo/gles2",
   ]
 }