ozone: evdev: Add gamepad support

ui/events/ozone/gamepad/gamepad_provider_ozone.cc

+// 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.
+
+#include "ui/events/ozone/gamepad/gamepad_provider_ozone.h"
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "ui/events/ozone/gamepad/gamepad_observer.h"
+
+namespace ui {
+
+GamepadProviderOzone::GamepadProviderOzone() {}
+
+GamepadProviderOzone::~GamepadProviderOzone() {}
+
+GamepadProviderOzone* GamepadProviderOzone::GetInstance() {
+  // GamepadProviderOzone is not holding any important resource. It's best to be
+  // leaky to reduce shutdown time.
+  return base::Singleton<
+      GamepadProviderOzone,
+      base::LeakySingletonTraits<GamepadProviderOzone>>::get();
+}
+
+void GamepadProviderOzone::DispatchGamepadDevicesUpdated(
+    std::vector<InputDevice> gamepad_devices) {
+  gamepad_devices_.swap(gamepad_devices);
+  for (auto ite = observers_.begin(); ite != observers_.end(); ++ite) {
+    (*ite)->OnGamepadDevicesUpdated();
+  }
+}
+
+void GamepadProviderOzone::DispatchGamepadEvent(const GamepadEvent& event) {
+  for (auto ite = observers_.begin(); ite != observers_.end(); ++ite) {
+    (*ite)->OnGamepadEvent(event);
+  }
+}
+
+void GamepadProviderOzone::AddGamepadObserver(GamepadObserver* observer) {
+  observers_.insert(observer);
+}
+
+void GamepadProviderOzone::RemoveGamepadObserver(GamepadObserver* observer) {
+  observers_.erase(observer);
+}
+
+std::vector<InputDevice> GamepadProviderOzone::GetGamepadDevices() {
+  return gamepad_devices_;
+}
+}  // namespace ui