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

ui/events/devices/x11/BUILD.gn

+# Copyright 2016 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 = "events_devices_x11"
+
+  sources = [
+    "device_data_manager_x11.cc",
+    "device_data_manager_x11.h",
+    "device_list_cache_x11.cc",
+    "device_list_cache_x11.h",
+    "events_devices_x11_export.h",
+    "touch_factory_x11.cc",
+    "touch_factory_x11.h",
+  ]
+
+  configs += [ "//build/config/linux:x11" ]
+
+  defines = [ "EVENTS_DEVICES_X11_IMPLEMENTATION" ]
+
+  deps = [
+    "//base",
+    "//base/third_party/dynamic_annotations",
+    "//skia",
+    "//ui/events:events_base",
+    "//ui/events/devices",
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+    "//ui/gfx/x",
+  ]
+}