Allow gaming_seat to use ozone gamepad as back-end

components/exo/gaming_seat_ozone.cc

Index: components/exo/gaming_seat_ozone.cc
diff --git a/components/exo/gaming_seat_ozone.cc b/components/exo/gaming_seat_ozone.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0429e95c925c8ab452ba365b21bb87808cef4db3
--- /dev/null
+++ b/components/exo/gaming_seat_ozone.cc
@@ -0,0 +1,108 @@
+// 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 "components/exo/gamepad_delegate.h"
+#include "components/exo/gaming_seat.h"
+#include "components/exo/gaming_seat_delegate.h"
+#include "components/exo/shell_surface.h"
+#include "components/exo/surface.h"
+#include "ui/events/ozone/gamepad/gamepad_provider_ozone.h"
+
+namespace exo {
+
+////////////////////////////////////////////////////////////////////////////////
+// GamingSeat, public:
+
+GamingSeat::GamingSeat(GamingSeatDelegate* delegate,
+                       base::SingleThreadTaskRunner* task_runner)
+    : delegate_(delegate) {
+  auto* helper = WMHelper::GetInstance();
+  helper->AddFocusObserver(this);
+  OnWindowFocused(helper->GetFocusedWindow(), nullptr);
+}
+
+GamingSeat::~GamingSeat() {
+  ui::GamepadProviderOzone::GetInstance()->RemoveGamepadObserver(this);
+  delegate_->OnGamingSeatDestroying(this);
+  // Disconnect all the gamepads.
+  for (auto& entry : gamepads_)
+    entry.second->OnRemoved();
+
+  WMHelper::GetInstance()->RemoveFocusObserver(this);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// WMHelper::FocusObserver overrides:
+
+void GamingSeat::OnWindowFocused(aura::Window* gained_focus,
+                                 aura::Window* lost_focus) {
+  Surface* target = nullptr;
+  if (gained_focus) {
+    target = Surface::AsSurface(gained_focus);
+    if (!target) {
+      aura::Window* top_level_window = gained_focus->GetToplevelWindow();
+      if (top_level_window)
+        target = ShellSurface::GetMainSurface(top_level_window);
+    }
+  }
+
+  bool focused = target && delegate_->CanAcceptGamepadEventsForSurface(target);
+  if (focused) {
+    ui::GamepadProviderOzone::GetInstance()->AddGamepadObserver(this);
+    OnGamepadDevicesUpdated();
+  } else {
+    ui::GamepadProviderOzone::GetInstance()->RemoveGamepadObserver(this);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ui::GamepadObserver overrides:
+
+void GamingSeat::OnGamepadDevicesUpdated() {
+  std::vector<ui::InputDevice> gamepad_devices =
+      ui::GamepadProviderOzone::GetInstance()->GetGamepadDevices();
+
+  base::flat_map<int, GamepadDelegate*> new_gamepads;
+
+  // Copy the "still connected gamepads".
+  for (auto& device : gamepad_devices) {
+    auto it = gamepads_.find(device.id);
+    if (it != gamepads_.end()) {
+      new_gamepads[device.id] = it->second;
+      gamepads_.erase(it);
+    }
+  }
+
+  // Remove each disconected gamepad.
+  for (auto& entry : gamepads_)
+    entry.second->OnRemoved();
+
+  // Add each new connected gamepad.
+  for (auto& device : gamepad_devices) {
+    if (new_gamepads.find(device.id) == new_gamepads.end())
+      new_gamepads[device.id] = delegate_->GamepadAdded();
+  }
+
+  new_gamepads.swap(gamepads_);
+}
+
+void GamingSeat::OnGamepadEvent(const ui::GamepadEvent& event) {
+  auto it = gamepads_.find(event.device_id());
+  if (it == gamepads_.end())
+    return;
+
+  switch (event.type()) {
+    case ui::GamepadEventType::BUTTON:
+      it->second->OnButton(event.code(), event.value(), event.value());
+      break;
+    case ui::GamepadEventType::AXIS:
+      it->second->OnAxis(event.code(), event.value());
+      break;
+    case ui::GamepadEventType::FRAME:
+      it->second->OnFrame();
+      break;
+  }
+}
+
+}  // namespace exo