Split //ui/events/devices into two targets.

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")
 import("//testing/test.gni")
 
 component("aura") {
   sources = [
     "../wm/public/activation_change_observer.cc",
@@ skipping 98 matching lines @@
   ]
 
   if (use_x11) {
     configs += [
       "//build/config/linux:x11",
       "//build/config/linux:xrandr",
     ]
     deps += [
       "//ui/events:events_base",
       "//ui/events/devices",
+      "//ui/events/devices/x11",
       "//ui/events/platform/x11",
       "//ui/gfx/x",
     ]
   } else {
     sources -= [
       "window_tree_host_x11.cc",
       "window_tree_host_x11.h",
     ]
   }
 
@@ skipping 143 matching lines @@
   ]
 
   if (is_linux) {
     deps += [ "//third_party/mesa" ]
   }
 
   data_deps = [
     "//third_party/mesa:osmesa",
   ]
 }