Keyboard Lock Host implementation

components/keyboard_lock/register_once_key_hook.h

Index: components/keyboard_lock/register_once_key_hook.h
diff --git a/components/keyboard_lock/register_once_key_hook.h b/components/keyboard_lock/register_once_key_hook.h
new file mode 100644
index 0000000000000000000000000000000000000000..4f3e554453246cbf9d28951814ea22ef4d653500
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+++ b/components/keyboard_lock/register_once_key_hook.h
@@ -0,0 +1,29 @@
+// 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 COMPONENTE_KEYBOARD_LOCK_REGISTER_ONCE_KEY_HOOK_H_
+#define COMPONENTE_KEYBOARD_LOCK_REGISTER_ONCE_KEY_HOOK_H_
+
+#include "components/keyboard_lock/sync_key_hook.h"
+
+namespace keyboard_lock {
+
+class RegisterOnceKeyHook : public SyncKeyHook {
+ public:
+  RegisterOnceKeyHook();
+  ~RegisterOnceKeyHook() override;
+
+  bool RegisterKey(const std::vector<ui::KeyboardCode>& codes) override;
+  bool UnregisterKey(const std::vector<ui::KeyboardCode>& codes) override;
+
+ private:
+  virtual bool Register() = 0;
+  virtual bool Unregister() = 0;
+
+  int count_ = 0;
+};
+
+}  // namespace keyboard_lock
+
+#endif  // COMPONENTE_KEYBOARD_LOCK_REGISTER_ONCE_KEY_HOOK_H_