Move base::FreeDeleter into its own header.

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc

 // 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.
 
 #include "ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h"
 
 #include <stddef.h>
 #include <xkbcommon/xkbcommon-names.h>
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/memory/free_deleter.h"
 #include "base/single_thread_task_runner.h"
 #include "base/task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/worker_pool.h"
 #include "build/build_config.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/keycodes/dom/dom_code.h"
 #include "ui/events/keycodes/dom/dom_key.h"
 #include "ui/events/keycodes/dom/keycode_converter.h"
 #include "ui/events/keycodes/keyboard_code_conversion.h"
@@ skipping 943 matching lines @@
       close_index = layout_name.size();
     *layout_variant = layout_name.substr(parentheses_index + 1,
                                          close_index - parentheses_index - 1);
   } else if (dash_index != std::string::npos) {
     *layout_id = layout_name.substr(0, dash_index);
     *layout_variant = layout_name.substr(dash_index + 1);
   }
 }
 
 }  // namespace ui