exo: Implement wayland gamepad support

components/exo/gamepads_delegate.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_EXO_GAMEPADS_DELEGATE_H_
+#define COMPONENTS_EXO_GAMEPADS_DELEGATE_H_
+
+namespace exo {
+class Gamepads;
+
+// Handles events on multiple gamepads
+class GamepadsDelegate {
+ public:
+  // Gives the delegate a chance to clean up when the Gamepads instance is
+  // destroyed.
+  virtual void OnGamepadsDestroying(Gamepads* gamepads) = 0;
+
+  // Called when a new gamepad is connected. Each gamepad is assigned an id
+  // that is used to identify it in every subsequent call.
+  virtual void OnConnected(int id) = 0;
+
+  // Called when a gamepad is disconnected.
+  virtual void OnDisconnected(int id) = 0;
+
+  // Called when the user moved an axis of the gamepad. Valid axes are defined
+  // by the W3C 'standard gamepad' specification.
+  virtual void OnAxis(int id, int axis, double value) = 0;
+
+  // Called when the user pressed or moved a button of the gamepad.
+  // Valid buttons are defined by the W3C 'standard gamepad' specification.
+  virtual void OnButton(int id, int button, bool pressed, double value) = 0;
+
+  // Called after all gamepad information of this frame has been set and the
+  // client should evaluate the updated state.
+  virtual void OnFrame(int id) = 0;
+
+ protected:
+  virtual ~GamepadsDelegate() {}
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_GAMEPADS_DELEGATE_H_