[System-Keyboard-Lock] Add KeyboardLockHost and KeyEventInterceptor

components/keyboard_lock/key_event_interceptor_installer.h

+// Copyright 2017 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.
+
+#ifndef COMPONENTS_KEYBOARD_LOCK_KEY_EVENT_INTERCEPTOR_INSTALLER_H_
+#define COMPONENTS_KEYBOARD_LOCK_KEY_EVENT_INTERCEPTOR_INSTALLER_H_
+
+#include "components/keyboard_lock/key_event_interceptor.h"
+
+namespace keyboard_lock {
+
+class KeyboardLockHost;
+
+// Installs itself as the default implementation of KeyEventInterceptor in
+// KeyboardLockHost.
+class KeyEventInterceptorInstaller : public KeyEventInterceptor {
+ public:
+  ~KeyEventInterceptorInstaller() override;
+
+ protected:
+  KeyEventInterceptorInstaller(KeyboardLockHost* host);

[dtapuska, 2017/04/18 13:43:17]

Do you need a DISALLOW_COPY ?

[Hzj_jie, 2017/04/19 00:46:26]

Done.

+};
+
+}  // namespace keyboard_lock
+
+#endif  // COMPONENTS_KEYBOARD_LOCK_KEY_EVENT_INTERCEPTOR_INSTALLER_H_