Extract touchscreen device management into a generic manager

ui/events/platform/x11/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.
 
 component("x11") {
   output_name = "x11_events_platform"
 
   sources = [
     "x11_event_source.cc",
     "x11_event_source.h",
     "x11_event_source_glib.cc",
     "x11_event_source_libevent.cc",
   ]
 
   defines = [
     "EVENTS_IMPLEMENTATION",
   ]
 
   configs += [
     "//build/config/linux:x11",
   ]
 
   deps = [
     "//ui/events",
+    "//ui/events:events_base",
     "//ui/events/platform",
     "//ui/gfx/x",
   ]
 
   if (is_linux) {
     sources -= [
       "x11_event_source_libevent.cc",
     ]
 
     configs += [
       "//build/config/linux:glib",
     ]
   } else {
     sources -= [
       "x11_event_source_glib.cc",
     ]
   }
 }