Add Mojo IPC based input-device service.

components/mus/public/cpp/input_devices/input_device_client.h

+// Copyright 2016 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_MUS_PUBLIC_CPP_INPUT_DEVICES_INPUT_DEVICE_CLIENT_H_
+#define COMPONENTS_MUS_PUBLIC_CPP_INPUT_DEVICES_INPUT_DEVICE_CLIENT_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "components/mus/public/interfaces/input_devices/input_device_server.mojom.h"
+#include "mojo/public/cpp/bindings/array.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "ui/events/devices/input_device.h"
+#include "ui/events/devices/input_device_event_observer.h"
+#include "ui/events/devices/input_device_manager.h"
+#include "ui/events/devices/touchscreen_device.h"
+
+namespace input_device {
+
+// Allows in-process client code to register as a InputDeviceEventObserver and
+// get information about input-devices. InputDeviceClient itself acts as an
+// InputDeviceObserverMojo and registers to get updates from InputDeviceServer.
+// Essentially, InputDeviceClient forwards input-device events and caches
+// input-device state.
+//
+// One instance of InputDeviceClient should be instantiated in each process that
+// needs input-device information but doesn't have DeviceDataManager. The Mojo

[sadrul, 2016/06/10 18:01:49]

each *client

But I don't think this line is adding anything over what's already explained
above.

[kylechar, 2016/06/10 19:29:31]

Deleted that part of the comment.

+// app should call Connect() to register as a InputDeviceObserverMojo. Client
+// code can use InputDeviceManager and be agnostic to what is providing the
+// input-device information.
+class InputDeviceClient : public mojom::InputDeviceObserverMojo,
+                          public ui::InputDeviceManager {
+ public:
+  InputDeviceClient();
+  ~InputDeviceClient() override;
+
+  // Connects to mojo:mus as an observer on InputDeviceServer to receive input
+  // device updates.
+  void Connect(mojom::InputDeviceServerPtr server);
+
+  // ui::InputDeviceManager:
+  const std::vector<ui::InputDevice>& GetKeyboardDevices() const override;
+  const std::vector<ui::TouchscreenDevice>& GetTouchscreenDevices()
+      const override;
+  const std::vector<ui::InputDevice>& GetMouseDevices() const override;
+  const std::vector<ui::InputDevice>& GetTouchpadDevices() const override;
+
+  bool AreDeviceListsComplete() const override;
+  bool AreTouchscreensEnabled() const override;
+
+  void AddObserver(ui::InputDeviceEventObserver* observer) override;
+  void RemoveObserver(ui::InputDeviceEventObserver* observer) override;
+
+ private:
+  // mojom::InputDeviceObserverMojo:
+  void OnKeyboardDeviceConfigurationChanged(
+      mojo::Array<ui::InputDevice> devices) override;
+  void OnTouchscreenDeviceConfigurationChanged(
+      mojo::Array<ui::TouchscreenDevice> devices) override;
+  void OnMouseDeviceConfigurationChanged(
+      mojo::Array<ui::InputDevice> devices) override;
+  void OnTouchpadDeviceConfigurationChanged(
+      mojo::Array<ui::InputDevice> devices) override;
+  void OnDeviceListsComplete(
+      mojo::Array<ui::InputDevice> keyboard_devices,
+      mojo::Array<ui::TouchscreenDevice> touchscreen_devices,
+      mojo::Array<ui::InputDevice> mouse_devices,
+      mojo::Array<ui::InputDevice> touchpad_devices) override;
+
+  mojo::Binding<mojom::InputDeviceObserverMojo> binding_;
+
+  // Holds the list of input devices and signal that we have received the lists
+  // after initialization.
+  std::vector<ui::InputDevice> keyboard_devices_;
+  std::vector<ui::TouchscreenDevice> touchscreen_devices_;
+  std::vector<ui::InputDevice> mouse_devices_;
+  std::vector<ui::InputDevice> touchpad_devices_;
+  bool device_lists_complete_ = false;
+
+  // List of in-process observers.
+  base::ObserverList<ui::InputDeviceEventObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(InputDeviceClient);
+};
+
+}  // namespace input_device
+
+#endif  // COMPONENTS_MUS_PUBLIC_CPP_INPUT_DEVICES_INPUT_DEVICE_CLIENT_H_