1 files changed, 664 insertions, 0 deletions
diff --git a/dom/gamepad/GamepadManager.cpp b/dom/gamepad/GamepadManager.cpp
new file mode 100644
index 0000000000..959b55310e
--- /dev/null
+++ b/dom/gamepad/GamepadManager.cpp
@@ -0,0 +1,664 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/GamepadManager.h"
+
+#include "mozilla/dom/Gamepad.h"
+#include "mozilla/dom/GamepadAxisMoveEvent.h"
+#include "mozilla/dom/GamepadButtonEvent.h"
+#include "mozilla/dom/GamepadEvent.h"
+#include "mozilla/dom/GamepadEventChannelChild.h"
+#include "mozilla/dom/GamepadMonitoring.h"
+#include "mozilla/dom/Promise.h"
+
+#include "mozilla/ipc/BackgroundChild.h"
+#include "mozilla/ipc/PBackgroundChild.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPtr.h"
+
+#include "nsContentUtils.h"
+#include "nsGlobalWindow.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsThreadUtils.h"
+#include "VRManagerChild.h"
+#include "mozilla/Services.h"
+#include "mozilla/Unused.h"
+
+#include <cstddef>
+
+using namespace mozilla::ipc;
+
+namespace mozilla::dom {
+
+namespace {
+
+const nsTArray<RefPtr<nsGlobalWindowInner>>::index_type NoIndex =
+    nsTArray<RefPtr<nsGlobalWindowInner>>::NoIndex;
+
+bool sShutdown = false;
+
+StaticRefPtr<GamepadManager> gGamepadManagerSingleton;
+
+// A threshold value of axis move to determine the first
+// intent.
+const float AXIS_FIRST_INTENT_THRESHOLD_VALUE = 0.1f;
+
+}  // namespace
+
+NS_IMPL_ISUPPORTS(GamepadManager, nsIObserver)
+
+GamepadManager::GamepadManager()
+    : mEnabled(false),
+      mNonstandardEventsEnabled(false),
+      mShuttingDown(false),
+      mPromiseID(0) {}
+
+nsresult GamepadManager::Init() {
+  mEnabled = StaticPrefs::dom_gamepad_enabled();
+  mNonstandardEventsEnabled =
+      StaticPrefs::dom_gamepad_non_standard_events_enabled();
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+
+  if (NS_WARN_IF(!observerService)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv;
+  rv = observerService->AddObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID,
+                                    false);
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GamepadManager::Observe(nsISupports* aSubject, const char* aTopic,
+                        const char16_t* aData) {
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (observerService) {
+    observerService->RemoveObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID);
+  }
+  BeginShutdown();
+  return NS_OK;
+}
+
+void GamepadManager::StopMonitoring() {
+  if (mChannelChild) {
+    PGamepadEventChannelChild::Send__delete__(mChannelChild);
+    mChannelChild = nullptr;
+  }
+  if (gfx::VRManagerChild::IsCreated()) {
+    gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
+    vm->SendControllerListenerRemoved();
+  }
+  mGamepads.Clear();
+}
+
+void GamepadManager::BeginShutdown() {
+  mShuttingDown = true;
+  StopMonitoring();
+  // Don't let windows call back to unregister during shutdown
+  for (uint32_t i = 0; i < mListeners.Length(); i++) {
+    mListeners[i]->SetHasGamepadEventListener(false);
+  }
+  mListeners.Clear();
+  sShutdown = true;
+}
+
+void GamepadManager::AddListener(nsGlobalWindowInner* aWindow) {
+  MOZ_ASSERT(aWindow);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // IPDL child has not been created
+  if (!mChannelChild) {
+    PBackgroundChild* actor = BackgroundChild::GetOrCreateForCurrentThread();
+    if (NS_WARN_IF(!actor)) {
+      // We are probably shutting down.
+      return;
+    }
+
+    RefPtr<GamepadEventChannelChild> child(GamepadEventChannelChild::Create());
+    if (!actor->SendPGamepadEventChannelConstructor(child.get())) {
+      // We are probably shutting down.
+      return;
+    }
+
+    mChannelChild = child;
+
+    if (gfx::VRManagerChild::IsCreated()) {
+      // Construct VRManagerChannel and ask adding the connected
+      // VR controllers to GamepadManager
+      gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
+      vm->SendControllerListenerAdded();
+    }
+  }
+
+  if (!mEnabled || mShuttingDown ||
+      nsContentUtils::ShouldResistFingerprinting(aWindow->GetExtantDoc())) {
+    return;
+  }
+
+  if (mListeners.IndexOf(aWindow) != NoIndex) {
+    return;  // already exists
+  }
+
+  mListeners.AppendElement(aWindow);
+}
+
+void GamepadManager::RemoveListener(nsGlobalWindowInner* aWindow) {
+  MOZ_ASSERT(aWindow);
+
+  if (mShuttingDown) {
+    // Doesn't matter at this point. It's possible we're being called
+    // as a result of our own destructor here, so just bail out.
+    return;
+  }
+
+  if (mListeners.IndexOf(aWindow) == NoIndex) {
+    return;  // doesn't exist
+  }
+
+  for (auto iter = mGamepads.Iter(); !iter.Done(); iter.Next()) {
+    aWindow->RemoveGamepad(iter.Key());
+  }
+
+  mListeners.RemoveElement(aWindow);
+
+  if (mListeners.IsEmpty()) {
+    StopMonitoring();
+  }
+}
+
+already_AddRefed<Gamepad> GamepadManager::GetGamepad(
+    GamepadHandle aHandle) const {
+  RefPtr<Gamepad> gamepad;
+  if (mGamepads.Get(aHandle, getter_AddRefs(gamepad))) {
+    return gamepad.forget();
+  }
+
+  return nullptr;
+}
+
+void GamepadManager::AddGamepad(GamepadHandle aHandle, const nsAString& aId,
+                                GamepadMappingType aMapping, GamepadHand aHand,
+                                uint32_t aDisplayID, uint32_t aNumButtons,
+                                uint32_t aNumAxes, uint32_t aNumHaptics,
+                                uint32_t aNumLightIndicator,
+                                uint32_t aNumTouchEvents) {
+  // TODO: bug 852258: get initial button/axis state
+  RefPtr<Gamepad> newGamepad =
+      new Gamepad(nullptr, aId,
+                  0,  // index is set by global window
+                  aHandle, aMapping, aHand, aDisplayID, aNumButtons, aNumAxes,
+                  aNumHaptics, aNumLightIndicator, aNumTouchEvents);
+
+  // We store the gamepad related to its index given by the parent process,
+  // and no duplicate index is allowed.
+  MOZ_ASSERT(!mGamepads.Get(aHandle, nullptr));
+  mGamepads.Put(aHandle, std::move(newGamepad));
+  NewConnectionEvent(aHandle, true);
+}
+
+void GamepadManager::RemoveGamepad(GamepadHandle aHandle) {
+  RefPtr<Gamepad> gamepad = GetGamepad(aHandle);
+  if (!gamepad) {
+    NS_WARNING("Trying to delete gamepad with invalid index");
+    return;
+  }
+  gamepad->SetConnected(false);
+  NewConnectionEvent(aHandle, false);
+  mGamepads.Remove(aHandle);
+}
+
+void GamepadManager::FireButtonEvent(EventTarget* aTarget, Gamepad* aGamepad,
+                                     uint32_t aButton, double aValue) {
+  nsString name =
+      aValue == 1.0L ? u"gamepadbuttondown"_ns : u"gamepadbuttonup"_ns;
+  GamepadButtonEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mGamepad = aGamepad;
+  init.mButton = aButton;
+  RefPtr<GamepadButtonEvent> event =
+      GamepadButtonEvent::Constructor(aTarget, name, init);
+
+  event->SetTrusted(true);
+
+  aTarget->DispatchEvent(*event);
+}
+
+void GamepadManager::FireAxisMoveEvent(EventTarget* aTarget, Gamepad* aGamepad,
+                                       uint32_t aAxis, double aValue) {
+  GamepadAxisMoveEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mGamepad = aGamepad;
+  init.mAxis = aAxis;
+  init.mValue = aValue;
+  RefPtr<GamepadAxisMoveEvent> event =
+      GamepadAxisMoveEvent::Constructor(aTarget, u"gamepadaxismove"_ns, init);
+
+  event->SetTrusted(true);
+
+  aTarget->DispatchEvent(*event);
+}
+
+void GamepadManager::NewConnectionEvent(GamepadHandle aHandle,
+                                        bool aConnected) {
+  if (mShuttingDown) {
+    return;
+  }
+
+  RefPtr<Gamepad> gamepad = GetGamepad(aHandle);
+  if (!gamepad) {
+    return;
+  }
+
+  // Hold on to listeners in a separate array because firing events
+  // can mutate the mListeners array.
+  nsTArray<RefPtr<nsGlobalWindowInner>> listeners(mListeners.Clone());
+
+  if (aConnected) {
+    for (uint32_t i = 0; i < listeners.Length(); i++) {
+#ifdef NIGHTLY_BUILD
+      // Don't fire a gamepadconnected event unless it's a secure context
+      if (!listeners[i]->IsSecureContext()) {
+        continue;
+      }
+#endif
+
+      // Do not fire gamepadconnected and gamepaddisconnected events when
+      // privacy.resistFingerprinting is true.
+      if (nsContentUtils::ShouldResistFingerprinting(
+              listeners[i]->GetExtantDoc())) {
+        continue;
+      }
+
+      // Only send events to non-background windows
+      if (!listeners[i]->IsCurrentInnerWindow() ||
+          listeners[i]->GetOuterWindow()->IsBackground()) {
+        continue;
+      }
+
+      // We don't fire a connected event here unless the window
+      // has seen input from at least one device.
+      if (!listeners[i]->HasSeenGamepadInput()) {
+        continue;
+      }
+
+      SetWindowHasSeenGamepad(listeners[i], aHandle);
+
+      RefPtr<Gamepad> listenerGamepad = listeners[i]->GetGamepad(aHandle);
+      if (listenerGamepad) {
+        // Fire event
+        FireConnectionEvent(listeners[i], listenerGamepad, aConnected);
+      }
+    }
+  } else {
+    // For disconnection events, fire one at every window that has received
+    // data from this gamepad.
+    for (uint32_t i = 0; i < listeners.Length(); i++) {
+      // Even background windows get these events, so we don't have to
+      // deal with the hassle of syncing the state of removed gamepads.
+
+      // Do not fire gamepadconnected and gamepaddisconnected events when
+      // privacy.resistFingerprinting is true.
+      if (nsContentUtils::ShouldResistFingerprinting(
+              listeners[i]->GetExtantDoc())) {
+        continue;
+      }
+
+      if (WindowHasSeenGamepad(listeners[i], aHandle)) {
+        RefPtr<Gamepad> listenerGamepad = listeners[i]->GetGamepad(aHandle);
+        if (listenerGamepad) {
+          listenerGamepad->SetConnected(false);
+          // Fire event
+          FireConnectionEvent(listeners[i], listenerGamepad, false);
+          listeners[i]->RemoveGamepad(aHandle);
+        }
+      }
+    }
+  }
+}
+
+void GamepadManager::FireConnectionEvent(EventTarget* aTarget,
+                                         Gamepad* aGamepad, bool aConnected) {
+  nsString name =
+      aConnected ? u"gamepadconnected"_ns : u"gamepaddisconnected"_ns;
+  GamepadEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mGamepad = aGamepad;
+  RefPtr<GamepadEvent> event = GamepadEvent::Constructor(aTarget, name, init);
+
+  event->SetTrusted(true);
+
+  aTarget->DispatchEvent(*event);
+}
+
+void GamepadManager::SyncGamepadState(GamepadHandle aHandle,
+                                      nsGlobalWindowInner* aWindow,
+                                      Gamepad* aGamepad) {
+  if (mShuttingDown || !mEnabled ||
+      nsContentUtils::ShouldResistFingerprinting(aWindow->GetExtantDoc())) {
+    return;
+  }
+
+  RefPtr<Gamepad> gamepad = GetGamepad(aHandle);
+  if (!gamepad) {
+    return;
+  }
+
+  aGamepad->SyncState(gamepad);
+}
+
+// static
+bool GamepadManager::IsServiceRunning() { return !!gGamepadManagerSingleton; }
+
+// static
+already_AddRefed<GamepadManager> GamepadManager::GetService() {
+  if (sShutdown) {
+    return nullptr;
+  }
+
+  if (!gGamepadManagerSingleton) {
+    RefPtr<GamepadManager> manager = new GamepadManager();
+    nsresult rv = manager->Init();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return nullptr;
+    }
+    gGamepadManagerSingleton = manager;
+    ClearOnShutdown(&gGamepadManagerSingleton);
+  }
+
+  RefPtr<GamepadManager> service(gGamepadManagerSingleton);
+  return service.forget();
+}
+
+bool GamepadManager::AxisMoveIsFirstIntent(nsGlobalWindowInner* aWindow,
+                                           GamepadHandle aHandle,
+                                           const GamepadChangeEvent& aEvent) {
+  const GamepadChangeEventBody& body = aEvent.body();
+  if (!WindowHasSeenGamepad(aWindow, aHandle) &&
+      body.type() == GamepadChangeEventBody::TGamepadAxisInformation) {
+    // Some controllers would send small axis values even they are just idle.
+    // To avoid controllers be activated without its first intent.
+    const GamepadAxisInformation& a = body.get_GamepadAxisInformation();
+    if (abs(a.value()) < AXIS_FIRST_INTENT_THRESHOLD_VALUE) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool GamepadManager::MaybeWindowHasSeenGamepad(nsGlobalWindowInner* aWindow,
+                                               GamepadHandle aHandle) {
+  if (!WindowHasSeenGamepad(aWindow, aHandle)) {
+    // This window hasn't seen this gamepad before, so
+    // send a connection event first.
+    SetWindowHasSeenGamepad(aWindow, aHandle);
+    return false;
+  }
+  return true;
+}
+
+bool GamepadManager::WindowHasSeenGamepad(nsGlobalWindowInner* aWindow,
+                                          GamepadHandle aHandle) const {
+  RefPtr<Gamepad> gamepad = aWindow->GetGamepad(aHandle);
+  return gamepad != nullptr;
+}
+
+void GamepadManager::SetWindowHasSeenGamepad(nsGlobalWindowInner* aWindow,
+                                             GamepadHandle aHandle,
+                                             bool aHasSeen) {
+  MOZ_ASSERT(aWindow);
+
+  if (mListeners.IndexOf(aWindow) == NoIndex) {
+    // This window isn't even listening for gamepad events.
+    return;
+  }
+
+  if (aHasSeen) {
+    aWindow->SetHasSeenGamepadInput(true);
+    nsCOMPtr<nsISupports> window = ToSupports(aWindow);
+    RefPtr<Gamepad> gamepad = GetGamepad(aHandle);
+    if (!gamepad) {
+      return;
+    }
+    RefPtr<Gamepad> clonedGamepad = gamepad->Clone(window);
+    aWindow->AddGamepad(aHandle, clonedGamepad);
+  } else {
+    aWindow->RemoveGamepad(aHandle);
+  }
+}
+
+void GamepadManager::Update(const GamepadChangeEvent& aEvent) {
+  if (!mEnabled || mShuttingDown ||
+      nsContentUtils::ShouldResistFingerprinting()) {
+    return;
+  }
+
+  const GamepadHandle handle = aEvent.handle();
+
+  GamepadChangeEventBody body = aEvent.body();
+
+  if (body.type() == GamepadChangeEventBody::TGamepadAdded) {
+    const GamepadAdded& a = body.get_GamepadAdded();
+    AddGamepad(handle, a.id(), static_cast<GamepadMappingType>(a.mapping()),
+               static_cast<GamepadHand>(a.hand()), a.display_id(),
+               a.num_buttons(), a.num_axes(), a.num_haptics(), a.num_lights(),
+               a.num_touches());
+    return;
+  }
+  if (body.type() == GamepadChangeEventBody::TGamepadRemoved) {
+    RemoveGamepad(handle);
+    return;
+  }
+
+  if (!SetGamepadByEvent(aEvent)) {
+    return;
+  }
+
+  // Hold on to listeners in a separate array because firing events
+  // can mutate the mListeners array.
+  nsTArray<RefPtr<nsGlobalWindowInner>> listeners(mListeners.Clone());
+
+  for (uint32_t i = 0; i < listeners.Length(); i++) {
+    // Only send events to non-background windows
+    if (!listeners[i]->IsCurrentInnerWindow() ||
+        listeners[i]->GetOuterWindow()->IsBackground()) {
+      continue;
+    }
+
+    SetGamepadByEvent(aEvent, listeners[i]);
+    MaybeConvertToNonstandardGamepadEvent(aEvent, listeners[i]);
+  }
+}
+
+void GamepadManager::MaybeConvertToNonstandardGamepadEvent(
+    const GamepadChangeEvent& aEvent, nsGlobalWindowInner* aWindow) {
+  MOZ_ASSERT(aWindow);
+
+  if (!mNonstandardEventsEnabled) {
+    return;
+  }
+
+  GamepadHandle handle = aEvent.handle();
+
+  RefPtr<Gamepad> gamepad = aWindow->GetGamepad(handle);
+  const GamepadChangeEventBody& body = aEvent.body();
+
+  if (gamepad) {
+    switch (body.type()) {
+      case GamepadChangeEventBody::TGamepadButtonInformation: {
+        const GamepadButtonInformation& a = body.get_GamepadButtonInformation();
+        FireButtonEvent(aWindow, gamepad, a.button(), a.value());
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadAxisInformation: {
+        const GamepadAxisInformation& a = body.get_GamepadAxisInformation();
+        FireAxisMoveEvent(aWindow, gamepad, a.axis(), a.value());
+        break;
+      }
+      default:
+        break;
+    }
+  }
+}
+
+bool GamepadManager::SetGamepadByEvent(const GamepadChangeEvent& aEvent,
+                                       nsGlobalWindowInner* aWindow) {
+  bool ret = false;
+  bool firstTime = false;
+
+  GamepadHandle handle = aEvent.handle();
+
+  if (aWindow) {
+    if (!AxisMoveIsFirstIntent(aWindow, handle, aEvent)) {
+      return false;
+    }
+    firstTime = !MaybeWindowHasSeenGamepad(aWindow, handle);
+  }
+
+  RefPtr<Gamepad> gamepad =
+      aWindow ? aWindow->GetGamepad(handle) : GetGamepad(handle);
+  const GamepadChangeEventBody& body = aEvent.body();
+
+  if (gamepad) {
+    switch (body.type()) {
+      case GamepadChangeEventBody::TGamepadButtonInformation: {
+        const GamepadButtonInformation& a = body.get_GamepadButtonInformation();
+        gamepad->SetButton(a.button(), a.pressed(), a.touched(), a.value());
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadAxisInformation: {
+        const GamepadAxisInformation& a = body.get_GamepadAxisInformation();
+        gamepad->SetAxis(a.axis(), a.value());
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadPoseInformation: {
+        const GamepadPoseInformation& a = body.get_GamepadPoseInformation();
+        gamepad->SetPose(a.pose_state());
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadLightIndicatorTypeInformation: {
+        const GamepadLightIndicatorTypeInformation& a =
+            body.get_GamepadLightIndicatorTypeInformation();
+        gamepad->SetLightIndicatorType(a.light(), a.type());
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadTouchInformation: {
+        // Avoid GamepadTouch's touchId be accessed in cross-origin tracking.
+        for (uint32_t i = 0; i < mListeners.Length(); i++) {
+          RefPtr<Gamepad> listenerGamepad = mListeners[i]->GetGamepad(handle);
+          if (listenerGamepad && mListeners[i]->IsCurrentInnerWindow() &&
+              !mListeners[i]->GetOuterWindow()->IsBackground()) {
+            const GamepadTouchInformation& a =
+                body.get_GamepadTouchInformation();
+            listenerGamepad->SetTouchEvent(a.index(), a.touch_state());
+          }
+        }
+        break;
+      }
+      case GamepadChangeEventBody::TGamepadHandInformation: {
+        const GamepadHandInformation& a = body.get_GamepadHandInformation();
+        gamepad->SetHand(a.hand());
+        break;
+      }
+      default:
+        MOZ_ASSERT(false);
+        break;
+    }
+    ret = true;
+  }
+
+  if (aWindow && firstTime) {
+    FireConnectionEvent(aWindow, gamepad, true);
+  }
+
+  return ret;
+}
+
+already_AddRefed<Promise> GamepadManager::VibrateHaptic(
+    GamepadHandle aHandle, uint32_t aHapticIndex, double aIntensity,
+    double aDuration, nsIGlobalObject* aGlobal, ErrorResult& aRv) {
+  RefPtr<Promise> promise = Promise::Create(aGlobal, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+  if (StaticPrefs::dom_gamepad_haptic_feedback_enabled()) {
+    if (aHandle.GetKind() == GamepadHandleKind::VR) {
+      if (gfx::VRManagerChild::IsCreated()) {
+        gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
+        vm->AddPromise(mPromiseID, promise);
+        vm->SendVibrateHaptic(aHandle, aHapticIndex, aIntensity, aDuration,
+                              mPromiseID);
+      }
+    } else {
+      if (mChannelChild) {
+        mChannelChild->AddPromise(mPromiseID, promise);
+        mChannelChild->SendVibrateHaptic(aHandle, aHapticIndex, aIntensity,
+                                         aDuration, mPromiseID);
+      }
+    }
+  }
+
+  ++mPromiseID;
+  return promise.forget();
+}
+
+void GamepadManager::StopHaptics() {
+  if (!StaticPrefs::dom_gamepad_haptic_feedback_enabled()) {
+    return;
+  }
+
+  for (auto iter = mGamepads.Iter(); !iter.Done(); iter.Next()) {
+    const GamepadHandle handle = iter.UserData()->GetHandle();
+    if (handle.GetKind() == GamepadHandleKind::VR) {
+      if (gfx::VRManagerChild::IsCreated()) {
+        gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
+        vm->SendStopVibrateHaptic(handle);
+      }
+    } else {
+      if (mChannelChild) {
+        mChannelChild->SendStopVibrateHaptic(handle);
+      }
+    }
+  }
+}
+
+already_AddRefed<Promise> GamepadManager::SetLightIndicatorColor(
+    GamepadHandle aHandle, uint32_t aLightColorIndex, uint8_t aRed,
+    uint8_t aGreen, uint8_t aBlue, nsIGlobalObject* aGlobal, ErrorResult& aRv) {
+  RefPtr<Promise> promise = Promise::Create(aGlobal, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+  if (StaticPrefs::dom_gamepad_extensions_lightindicator()) {
+    MOZ_RELEASE_ASSERT(aHandle.GetKind() != GamepadHandleKind::VR,
+                       "We don't support light indicator in VR.");
+
+    if (mChannelChild) {
+      mChannelChild->AddPromise(mPromiseID, promise);
+      mChannelChild->SendLightIndicatorColor(aHandle, aLightColorIndex, aRed,
+                                             aGreen, aBlue, mPromiseID);
+    }
+  }
+
+  ++mPromiseID;
+  return promise.forget();
+}
+}  // namespace mozilla::dom