Keyboard Lock Host implementation

components/keyboard_lock/sync_key_hook.h

Index: components/keyboard_lock/sync_key_hook.h
diff --git a/components/keyboard_lock/sync_key_hook.h b/components/keyboard_lock/sync_key_hook.h
new file mode 100644
index 0000000000000000000000000000000000000000..58416097a1d266371f2304b0ac60f31a52b368e6
--- /dev/null
+++ b/components/keyboard_lock/sync_key_hook.h
@@ -0,0 +1,31 @@
+// 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_SYNC_KEY_HOOK_H_
+#define COMPONENTS_KEYBOARD_LOCK_SYNC_KEY_HOOK_H_
+
+#include "components/keyboard_lock/key_hook.h"
+
+namespace keyboard_lock {
+
+// An implementation of KeyHook for synchronized implementation, i.e. both
+// RegisterKey() and UnregisterKey() return synchronizedly. Usually a platform
+// specific implementation should derived from this class.
+class SyncKeyHook : public KeyHook {
+ public:
+  SyncKeyHook();
+  ~SyncKeyHook() override;
+
+  void RegisterKey(const std::vector<ui::KeyboardCode>& codes,
+                   base::Callback<void(bool)> on_result) final;
+  void UnregisterKey(const std::vector<ui::KeyboardCode>& codes,
+                     base::Callback<void(bool)> on_result) final;
+
+  virtual bool RegisterKey(const std::vector<ui::KeyboardCode>& codes) = 0;
+  virtual bool UnregisterKey(const std::vector<ui::KeyboardCode>& codes) = 0;
+};
+
+}  // namespace keyboard_lock
+
+#endif  // COMPONENTS_KEYBOARD_LOCK_SYNC_KEY_HOOK_H_