Allow gaming_seat to use ozone gamepad as back-end

components/exo/gaming_seat_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 "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 {

[reveman, 2017/06/05 22:48:04]

nit: blank line after this

[jkwang, 2017/06/06 20:03:09]

Done.

+constexpr int kMaxGamepadCount = 4;

[reveman, 2017/06/05 22:48:04]

nit: s/constexpr/const/ as that's more consistent with exo code and please add a
short comment above this to explain the constant

[jkwang, 2017/06/06 20:03:08]

Done.

+}  // namespace

[reveman, 2017/06/05 22:48:04]

nit: blank line before this

[jkwang, 2017/06/06 20:03:09]

Done.

+
+namespace exo {
+
+base::Thread* GamingSeat::CreatePollingThreadIfNeeded() {
+  return nullptr;
+}
+
+GamingSeat::GamingSeat(GamingSeatDelegate* delegate,
+                       base::Thread* polling_thread)
+    : delegate_(delegate),
+      gamepad_provider_(ui::GamepadProviderOzone::GetInstance()) {
+  DCHECK(!polling_thread);
+  auto* helper = WMHelper::GetInstance();
+  helper->AddFocusObserver(this);
+  OnWindowFocused(helper->GetFocusedWindow(), nullptr);
+}
+
+GamingSeat::~GamingSeat() {
+  gamepad_provider_->RemoveGamepadObserver(this);
+  delegate_->OnGamingSeatDestroying(this);
+  // Disconnect all the gamepads.
+  for (auto& entry : gamepads_) {
+    entry.second->OnRemoved();
+  }
+
+  WMHelper::GetInstance()->RemoveFocusObserver(this);
+}
+
+void GamingSeat::OnWindowFocused(aura::Window* gained_focus,
+                                 aura::Window* lost_focus) {
+  Surface* target = nullptr;
+  if (gained_focus) {
+    target = Surface::AsSurface(gained_focus);
+    if (!target) {

[reveman, 2017/06/05 22:48:04]

hm, why is this scope needed?

[jkwang, 2017/06/06 20:03:08]

To be honest, I don't know. I am reusing the same logic from old gaming_seat.

+      aura::Window* top_level_window = gained_focus->GetToplevelWindow();
+      if (top_level_window)
+        target = ShellSurface::GetMainSurface(top_level_window);
+    }
+  }
+
+  bool focused = target && delegate_->CanAcceptGamepadEventsForSurface(target);
+  Enable(focused);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// GamingSeat, Override functions for GamepadObserver.
+void GamingSeat::OnGamepadDevicesUpdated() {
+  std::vector<ui::InputDevice> gamepad_devices =

[reveman, 2017/06/05 22:48:04]

hm, would be nice if GetGamepadDevices could return a reference instead of
making a copy of a vector

[jkwang, 2017/06/06 20:03:09]

Yes, it should! I have added it to my bug. But I will fix it in a following
patch cause I have to update ozone part. 

+      gamepad_provider_->GetGamepadDevices();
+
+  std::map<int, GamepadDelegate*> old_gamepad_map;

[reveman, 2017/06/05 22:48:04]

nit: old_gamepads and I would prefer new_gamepads and reverse the logic below to
swap at the end instead

[jkwang, 2017/06/06 20:03:08]

Done.

+  old_gamepad_map.swap(gamepads_);
+
+  // Copy the "still connected gamepads".
+  for (auto& device : gamepad_devices) {
+    auto ite = old_gamepad_map.find(device.id);

[reveman, 2017/06/05 22:48:04]

nit: s/ite/it/

[jkwang, 2017/06/06 20:03:09]

Done.

+    if (ite != old_gamepad_map.end()) {
+      gamepads_[device.id] = ite->second;
+      old_gamepad_map.erase(ite);
+    }
+  }
+
+  // Send event for the disconected gamepads.

[reveman, 2017/06/05 22:48:04]

nit: s/Send event for the/Remove each/
nit: s/disconected gamepads/disconnected gamepad/

[jkwang, 2017/06/06 20:03:09]

Done.

+  for (auto& entry : old_gamepad_map) {

[reveman, 2017/06/05 22:48:04]

nit: no need for {}

[jkwang, 2017/06/06 20:03:07]

Done.

+    entry.second->OnRemoved();
+  }
+
+  // Connect new connected gamepads if there is a slot.
+  for (auto& device : gamepad_devices) {
+    if (gamepads_.size() >= kMaxGamepadCount) {

[reveman, 2017/06/05 22:48:04]

nit: no need for {}

why do we need this kMaxGamepadCount limit?

[jkwang, 2017/06/06 20:03:08]

/device/gamepad support up to 4 gamepads. So android part only support 4
gamepads.
I added a todo item to check if we should remove this and change android later.
Done.

+      break;
+    }
+    if (gamepads_.find(device.id) == gamepads_.end()) {

[reveman, 2017/06/05 22:48:04]

nit: no need for {}

[jkwang, 2017/06/06 20:03:09]

Done.

+      gamepads_[device.id] = delegate_->GamepadAdded();
+    }
+  }
+}
+
+void GamingSeat::OnGamepadEvent(const ui::GamepadEvent& event) {
+  auto ite = gamepads_.find(event.device_id());

[reveman, 2017/06/05 22:48:04]

nit: s/ite/it/

[jkwang, 2017/06/06 20:03:09]

Done.

+  if (ite == gamepads_.end())

[reveman, 2017/06/05 22:48:04]

DCHECK after removing kMaxGamepadCount if possible

[jkwang, 2017/06/06 20:03:08]

Done.

+    return;
+
+  switch (event.type()) {
+    case ui::GamepadEventType::BUTTON:
+      ite->second->OnButton(event.code(), event.value(), event.value());
+      break;
+    case ui::GamepadEventType::AXIS:
+      ite->second->OnAxis(event.code(), event.value());
+      break;
+    case ui::GamepadEventType::FRAME:
+      ite->second->OnFrame();
+      break;
+  }
+}
+
+void GamingSeat::Enable(bool enable) {

[reveman, 2017/06/05 22:48:04]

Do we need this function? Your only calling it from one place and I think the
code would be easier to understand without it.

[jkwang, 2017/06/06 20:03:08]

Done.

+  if (enable) {
+    gamepad_provider_->AddGamepadObserver(this);
+    OnGamepadDevicesUpdated();
+  } else {
+    gamepad_provider_->RemoveGamepadObserver(this);
+  }
+}
+
+}  // namespace exo