[System-Keyboard-Lock] Add KeyboardLockHost and KeyEventInterceptor

components/keyboard_lock/keyboard_lock_host.h

Index: components/keyboard_lock/keyboard_lock_host.h
diff --git a/components/keyboard_lock/keyboard_lock_host.h b/components/keyboard_lock/keyboard_lock_host.h
new file mode 100644
index 0000000000000000000000000000000000000000..5aa3308419f4cd987f9b5b45d9bc3ae8cc7b4e23
--- /dev/null
+++ b/components/keyboard_lock/keyboard_lock_host.h
@@ -0,0 +1,34 @@
+// 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_KEYBOARD_LOCK_HOST_H_
+#define COMPONENTS_KEYBOARD_LOCK_KEYBOARD_LOCK_HOST_H_
+
+#include <memory>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace keyboard_lock {
+
+class KeyboardLockHost final {
+ public:
+  KeyboardLockHost(scoped_refptr<base::SingleThreadTaskRunner> runner);
+  ~KeyboardLockHost();
+
+ private:
+  const scoped_refptr<base::SingleThreadTaskRunner> runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(KeyboardLockHost);
+};
+
+}  // namespace keyboard_lock
+
+#endif  // COMPONENTS_KEYBOARD_LOCK_KEYBOARD_LOCK_HOST_H_