exo: Implement wayland gamepad support

components/exo/gamepad_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_GAMEPAD_DELEGATE_H_
+#define COMPONENTS_EXO_GAMEPAD_DELEGATE_H_
+
+#include "base/memory/weak_ptr.h"
+
+namespace exo {
+class Gamepad;
+
+// Handles events on multiple gamepad
+class GamepadDelegate {
+ public:
+  // Gives the delegate a chance to clean up when the Gamepad instance is
+  // destroyed.
+  virtual void OnGamepadDestroying(Gamepad* gamepad) = 0;
+
+  // Called when the state of the gamepad has changed.
+  virtual void OnStateChange(bool connected) = 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 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 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() = 0;
+
+  // Used to obtain a weak pointer to this delegate.
+  virtual base::WeakPtr<GamepadDelegate> GetWeakPtr() = 0;

[reveman, 2016/06/30 01:19:05]

Please handle this in the Gamepad implementation instead. The delegate is
supposed to be as simple as possible.

[denniskempin, 2016/06/30 17:08:29]

Done. Also no longer needed.

+
+ protected:
+  virtual ~GamepadDelegate() {}
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_GAMEPAD_DELEGATE_H_