Remove X11 deps from //ui/events:events_base.

ui/events/keycodes/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.
+
+import("//build/config/ui.gni")
+import("//ui/ozone/ozone.gni")
+
+source_set("xkb") {
+  sources = [
+    "keyboard_code_conversion_xkb.cc",
+    "keyboard_code_conversion_xkb.h",
+    "scoped_xkb.h",
+    "xkb_keysym.h",
+  ]
+
+  deps = [
+    "//base",
+    "//ui/events:dom_keycode_converter",
+  ]
+}
+
+if (use_x11 || ozone_platform_x11) {
+  component("x11") {
+    output_name = "keycodes_x11"
+
+    sources = [
+      "keyboard_code_conversion_x.cc",
+      "keyboard_code_conversion_x.h",
+      "keycodes_x_export.h",
+      "keysym_to_unicode.cc",
+      "keysym_to_unicode.h",
+    ]
+
+    defines = [ "KEYCODES_X_IMPLEMENTATION" ]
+
+    deps = [
+      ":xkb",
+      "//base",
+      "//ui/events:dom_keycode_converter",
+      "//ui/gfx/x",
+    ]
+
+    configs += [ "//build/config/linux:x11" ]
+  }
+}