[System-Keyboard-Lock] Add KeyboardLockHost and KeyEventInterceptor

components/keyboard_lock/keyboard_lock_host.cc

+// 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.
+
+#include "components/keyboard_lock/keyboard_lock_host.h"
+
+#include <utility>
+
+#include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+
+namespace keyboard_lock {
+
+KeyboardLockHost::KeyboardLockHost(
+    scoped_refptr<base::SingleThreadTaskRunner> runner)
+    : runner_(std::move(runner)) {
+  DCHECK(runner_);
+}
+
+KeyboardLockHost::~KeyboardLockHost() = default;
+
+}  // namespace keyboard_lock