Convert views X11 UnhandledKeyboardEventHandler to other Linux platforms

ui/views/controls/webview/unhandled_keyboard_event_handler_aurax11.cc

-// Copyright (c) 2012 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/views/controls/webview/unhandled_keyboard_event_handler.h"
-
-#include "base/logging.h"
-#include "content/public/browser/native_web_keyboard_event.h"
-#include "ui/events/event.h"
-#include "ui/views/focus/focus_manager.h"
-
-using content::NativeWebKeyboardEvent;
-
-namespace views {
-
-UnhandledKeyboardEventHandler::UnhandledKeyboardEventHandler() {
-}
-
-void UnhandledKeyboardEventHandler::HandleKeyboardEvent(
-    const NativeWebKeyboardEvent& event,
-    FocusManager* focus_manager) {
-  if (!focus_manager) {
-    NOTREACHED();
-    return;
-  }
-  if (event.os_event && !event.skip_in_browser)
-    focus_manager->OnKeyEvent(*static_cast<ui::KeyEvent*>(event.os_event));
-}
-
-}  // namespace views