Remove IPC::ParamTraits for ui::Event.

components/mus/common/BUILD.gn

 # Copyright 2015 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("//mojo/public/mojo_application_manifest.gni")
 import("//testing/test.gni")
 
 component("mus_common") {
   sources = [
     "event_matcher_util.cc",
     "event_matcher_util.h",
-    "event_param_traits.cc",
-    "event_param_traits.h",
-    "event_param_traits_macros.h",
     "gpu_memory_buffer_impl.cc",
     "gpu_memory_buffer_impl.h",
     "gpu_service.cc",
     "gpu_service.h",
     "gpu_type_converters.cc",
     "gpu_type_converters.h",
     "mojo_buffer_backing.cc",
     "mojo_buffer_backing.h",
     "mojo_gpu_memory_buffer.cc",
     "mojo_gpu_memory_buffer.h",
@@ skipping 40 matching lines @@
     "//services/shell/background:main",
   ]
 
   if (use_ozone) {
     deps += [ "//ui/ozone" ]
   }
 }
 
 test("mus_common_unittests") {
   sources = [
-    "event_param_traits_unittest.cc",
     "gpu_type_converters_unittest.cc",
   ]
   public_deps = [
     ":mus_common",
   ]
   deps = [
     ":run_all_shelltests",
     "//base",
     "//base/test:test_config",
     "//components/mus/public/interfaces",
     "//ipc:ipc",
     "//mojo/edk/test:test_support",
     "//testing/gtest",
-    "//ui/events:events",
     "//ui/gfx:test_support",
     "//ui/gfx/ipc",
   ]
 }
 
 mojo_application_manifest("mus_common_unittests_app_manifest") {
   application_name = "mus_common_unittests_app"
   source = "mus_common_unittests_app_manifest.json"
 }