[System-Keyboard-Lock] Add KeyboardLockHost and KeyEventInterceptor

components/keyboard_lock/keyboard_lock_host_unittest.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 "components/keyboard_lock/key_event_interceptor_installer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace keyboard_lock {
+
+namespace {
+
+class FakeKeyEventInterceptor : public KeyEventInterceptorInstaller {
+ public:
+  FakeKeyEventInterceptor(KeyboardLockHost* host)
+      : KeyEventInterceptorInstaller(host) {}
+  ~FakeKeyEventInterceptor() override { deleted_count++; }
+
+  bool OnKeyDown(ui::KeyboardCode code) override { return false; }
+  bool OnKeyUp(ui::KeyboardCode code) override { return false; }
+
+  static int deleted_count;
+};
+
+int FakeKeyEventInterceptor::deleted_count = 0;
+}
+
+TEST(KeyboardLockHostTest, KeyEventInterceptorInstallationTest) {
+  {
+    KeyboardLockHost host;
+    FakeKeyEventInterceptor* interceptor = new FakeKeyEventInterceptor(&host);
+    ASSERT_EQ(interceptor, host.interceptor());
+  }
+  ASSERT_EQ(FakeKeyEventInterceptor::deleted_count, 1);
+}
+
+}  // namespace keyboard_lock