Keyboard Lock Host implementation

components/keyboard_lock/key_hook_thread_wrapper.h

Index: components/keyboard_lock/key_hook_thread_wrapper.h
diff --git a/components/keyboard_lock/key_hook_thread_wrapper.h b/components/keyboard_lock/key_hook_thread_wrapper.h
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+++ b/components/keyboard_lock/key_hook_thread_wrapper.h
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+// 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_KEY_HOOK_THREAD_WRAPPER_H_
+#define COMPONENTS_KEYBOARD_LOCK_KEY_HOOK_THREAD_WRAPPER_H_
+
+#include <memory>
+
+#include "base/synchronization/lock.h"
+#include "components/keyboard_lock/key_event_filter.h"
+#include "components/keyboard_lock/key_hook_activator.h"
+
+namespace keyboard_lock {
+
+class KeyHookStateKeeper;
+
+// An implementation of both KeyHookActivator and KeyEventFilter to ensure all
+// the public functions are not called parallely from multiple threads.
+class KeyHookThreadWrapper final
+    : public KeyEventFilter,
+      public KeyHookActivator {
+ public:
+  // Takes ownership of both objects.
+  KeyHookThreadWrapper(std::unique_ptr<KeyEventFilter> filter,
+                       std::unique_ptr<KeyHookActivator> key_hook);
+  // A shortcut to create a KeyHookThreadWrapper from a KeyHookStateKeeper,
+  // which is the typical usage of this class.
+  explicit KeyHookThreadWrapper(
+      std::unique_ptr<KeyHookStateKeeper> state_keeper);
+  ~KeyHookThreadWrapper() override;
+
+  // KeyEventFilter implementations.
+  bool OnKeyDown(ui::KeyboardCode code, int flags) override;
+  bool OnKeyUp(ui::KeyboardCode code, int flags) override;
+
+  // KeyHookActivator implementations.
+  void RegisterKey(const std::vector<ui::KeyboardCode>& codes,
+                   base::Callback<void(bool)> on_result) override;
+  void UnregisterKey(const std::vector<ui::KeyboardCode>& codes,
+                     base::Callback<void(bool)> on_result) override;
+  void Activate(base::Callback<void(bool)> on_result) override;
+  void Deactivate(base::Callback<void(bool)> on_result) override;
+
+ private:
+  const std::unique_ptr<KeyEventFilter> filter_;
+  const std::unique_ptr<KeyHookActivator> key_hook_;
+  base::Lock lock_;
+};
+
+}  // namespace keyboard_lock
+
+#endif  // COMPONENTS_KEYBOARD_LOCK_KEY_HOOK_THREAD_WRAPPER_H_