16 files changed, 1212 insertions, 0 deletions
diff --git a/dom/power/PowerManagerService.cpp b/dom/power/PowerManagerService.cpp
new file mode 100644
index 0000000000..ad3eadce8e
--- /dev/null
+++ b/dom/power/PowerManagerService.cpp
@@ -0,0 +1,138 @@
+/* -*- 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/ContentParent.h"
+#include "mozilla/Hal.h"
+#include "mozilla/HalWakeLock.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/ModuleUtils.h"
+#include "mozilla/Preferences.h"
+#include "nsIDOMWakeLockListener.h"
+#include "PowerManagerService.h"
+#include "WakeLock.h"
+
+// For _exit().
+#ifdef XP_WIN
+#  include <process.h>
+#else
+#  include <unistd.h>
+#endif
+
+namespace mozilla::dom::power {
+
+using namespace hal;
+
+NS_IMPL_ISUPPORTS(PowerManagerService, nsIPowerManagerService)
+
+/* static */
+StaticRefPtr<PowerManagerService> PowerManagerService::sSingleton;
+
+/* static */
+already_AddRefed<PowerManagerService> PowerManagerService::GetInstance() {
+  if (!sSingleton) {
+    sSingleton = new PowerManagerService();
+    sSingleton->Init();
+    ClearOnShutdown(&sSingleton);
+  }
+
+  RefPtr<PowerManagerService> service = sSingleton.get();
+  return service.forget();
+}
+
+void PowerManagerService::Init() { RegisterWakeLockObserver(this); }
+
+PowerManagerService::~PowerManagerService() {
+  UnregisterWakeLockObserver(this);
+}
+
+void PowerManagerService::ComputeWakeLockState(
+    const WakeLockInformation& aWakeLockInfo, nsAString& aState) {
+  WakeLockState state = hal::ComputeWakeLockState(aWakeLockInfo.numLocks(),
+                                                  aWakeLockInfo.numHidden());
+  switch (state) {
+    case WAKE_LOCK_STATE_UNLOCKED:
+      aState.AssignLiteral("unlocked");
+      break;
+    case WAKE_LOCK_STATE_HIDDEN:
+      aState.AssignLiteral("locked-background");
+      break;
+    case WAKE_LOCK_STATE_VISIBLE:
+      aState.AssignLiteral("locked-foreground");
+      break;
+  }
+}
+
+void PowerManagerService::Notify(const WakeLockInformation& aWakeLockInfo) {
+  nsAutoString state;
+  ComputeWakeLockState(aWakeLockInfo, state);
+
+  /**
+   * Copy the listeners list before we walk through the callbacks
+   * because the callbacks may install new listeners. We expect no
+   * more than one listener per window, so it shouldn't be too long.
+   */
+  const CopyableAutoTArray<nsCOMPtr<nsIDOMMozWakeLockListener>, 2> listeners =
+      mWakeLockListeners;
+
+  for (uint32_t i = 0; i < listeners.Length(); ++i) {
+    listeners[i]->Callback(aWakeLockInfo.topic(), state);
+  }
+}
+
+NS_IMETHODIMP
+PowerManagerService::AddWakeLockListener(nsIDOMMozWakeLockListener* aListener) {
+  if (mWakeLockListeners.Contains(aListener)) return NS_OK;
+
+  mWakeLockListeners.AppendElement(aListener);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PowerManagerService::RemoveWakeLockListener(
+    nsIDOMMozWakeLockListener* aListener) {
+  mWakeLockListeners.RemoveElement(aListener);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PowerManagerService::GetWakeLockState(const nsAString& aTopic,
+                                      nsAString& aState) {
+  WakeLockInformation info;
+  GetWakeLockInfo(aTopic, &info);
+
+  ComputeWakeLockState(info, aState);
+
+  return NS_OK;
+}
+
+already_AddRefed<WakeLock> PowerManagerService::NewWakeLock(
+    const nsAString& aTopic, nsPIDOMWindowInner* aWindow,
+    mozilla::ErrorResult& aRv) {
+  RefPtr<WakeLock> wakelock = new WakeLock();
+  aRv = wakelock->Init(aTopic, aWindow);
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+
+  return wakelock.forget();
+}
+
+NS_IMETHODIMP
+PowerManagerService::NewWakeLock(const nsAString& aTopic,
+                                 mozIDOMWindow* aWindow,
+                                 nsIWakeLock** aWakeLock) {
+  mozilla::ErrorResult rv;
+  RefPtr<WakeLock> wakelock =
+      NewWakeLock(aTopic, nsPIDOMWindowInner::From(aWindow), rv);
+  if (rv.Failed()) {
+    return rv.StealNSResult();
+  }
+
+  wakelock.forget(aWakeLock);
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom::power
diff --git a/dom/power/PowerManagerService.h b/dom/power/PowerManagerService.h
new file mode 100644
index 0000000000..1522342201
--- /dev/null
+++ b/dom/power/PowerManagerService.h
@@ -0,0 +1,57 @@
+/* -*- 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/. */
+#ifndef mozilla_dom_power_PowerManagerService_h
+#define mozilla_dom_power_PowerManagerService_h
+
+#include "nsCOMPtr.h"
+#include "nsHashKeys.h"
+#include "nsTArray.h"
+#include "nsIDOMWakeLockListener.h"
+#include "nsIPowerManagerService.h"
+#include "mozilla/HalWakeLockInformation.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/dom/WakeLock.h"
+
+namespace mozilla::dom {
+
+class ContentParent;
+
+namespace power {
+
+class PowerManagerService : public nsIPowerManagerService,
+                            public hal::WakeLockObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPOWERMANAGERSERVICE
+
+  PowerManagerService() = default;
+
+  static already_AddRefed<PowerManagerService> GetInstance();
+
+  void Init();
+
+  // Implement WakeLockObserver
+  void Notify(const hal::WakeLockInformation& aWakeLockInfo) override;
+
+  already_AddRefed<WakeLock> NewWakeLock(const nsAString& aTopic,
+                                         nsPIDOMWindowInner* aWindow,
+                                         mozilla::ErrorResult& aRv);
+
+ private:
+  ~PowerManagerService();
+
+  void ComputeWakeLockState(const hal::WakeLockInformation& aWakeLockInfo,
+                            nsAString& aState);
+
+  static StaticRefPtr<PowerManagerService> sSingleton;
+
+  nsTArray<nsCOMPtr<nsIDOMMozWakeLockListener>> mWakeLockListeners;
+};
+
+}  // namespace power
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_power_PowerManagerService_h
diff --git a/dom/power/WakeLock.cpp b/dom/power/WakeLock.cpp
new file mode 100644
index 0000000000..b381b3c627
--- /dev/null
+++ b/dom/power/WakeLock.cpp
@@ -0,0 +1,181 @@
+/* -*- 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 "WakeLock.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/Event.h"  // for Event
+#include "mozilla/Hal.h"
+#include "mozilla/HalWakeLock.h"
+#include "nsError.h"
+#include "mozilla/dom/Document.h"
+#include "nsPIDOMWindow.h"
+#include "nsIPropertyBag2.h"
+
+using namespace mozilla::hal;
+
+namespace mozilla::dom {
+
+NS_INTERFACE_MAP_BEGIN(WakeLock)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY(nsIWakeLock)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_ADDREF(WakeLock)
+NS_IMPL_RELEASE(WakeLock)
+
+WakeLock::~WakeLock() {
+  DoUnlock();
+  DetachEventListener();
+}
+
+nsresult WakeLock::Init(const nsAString& aTopic, nsPIDOMWindowInner* aWindow) {
+  // Don't Init() a WakeLock twice.
+  MOZ_ASSERT(mTopic.IsEmpty());
+
+  if (aTopic.IsEmpty()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  mTopic.Assign(aTopic);
+
+  mWindow = do_GetWeakReference(aWindow);
+
+  /**
+   * Null windows are allowed. A wake lock without associated window
+   * is always considered invisible.
+   */
+  if (aWindow) {
+    nsCOMPtr<Document> doc = aWindow->GetExtantDoc();
+    NS_ENSURE_STATE(doc);
+    mHidden = doc->Hidden();
+  }
+
+  AttachEventListener();
+  DoLock();
+
+  return NS_OK;
+}
+
+void WakeLock::DoLock() {
+  if (!mLocked) {
+    // Change the flag immediately to prevent recursive reentering
+    mLocked = true;
+
+    hal::ModifyWakeLock(
+        mTopic, hal::WAKE_LOCK_ADD_ONE,
+        mHidden ? hal::WAKE_LOCK_ADD_ONE : hal::WAKE_LOCK_NO_CHANGE);
+  }
+}
+
+void WakeLock::DoUnlock() {
+  if (mLocked) {
+    // Change the flag immediately to prevent recursive reentering
+    mLocked = false;
+
+    hal::ModifyWakeLock(
+        mTopic, hal::WAKE_LOCK_REMOVE_ONE,
+        mHidden ? hal::WAKE_LOCK_REMOVE_ONE : hal::WAKE_LOCK_NO_CHANGE);
+  }
+}
+
+void WakeLock::AttachEventListener() {
+  if (nsCOMPtr<nsPIDOMWindowInner> window = do_QueryReferent(mWindow)) {
+    nsCOMPtr<Document> doc = window->GetExtantDoc();
+    if (doc) {
+      doc->AddSystemEventListener(u"visibilitychange"_ns, this,
+                                  /* useCapture = */ true,
+                                  /* wantsUntrusted = */ false);
+
+      nsCOMPtr<EventTarget> target = do_QueryInterface(window);
+      target->AddSystemEventListener(u"pagehide"_ns, this,
+                                     /* useCapture = */ true,
+                                     /* wantsUntrusted = */ false);
+      target->AddSystemEventListener(u"pageshow"_ns, this,
+                                     /* useCapture = */ true,
+                                     /* wantsUntrusted = */ false);
+    }
+  }
+}
+
+void WakeLock::DetachEventListener() {
+  if (nsCOMPtr<nsPIDOMWindowInner> window = do_QueryReferent(mWindow)) {
+    nsCOMPtr<Document> doc = window->GetExtantDoc();
+    if (doc) {
+      doc->RemoveSystemEventListener(u"visibilitychange"_ns, this,
+                                     /* useCapture = */ true);
+      nsCOMPtr<EventTarget> target = do_QueryInterface(window);
+      target->RemoveSystemEventListener(u"pagehide"_ns, this,
+                                        /* useCapture = */ true);
+      target->RemoveSystemEventListener(u"pageshow"_ns, this,
+                                        /* useCapture = */ true);
+    }
+  }
+}
+
+void WakeLock::Unlock(ErrorResult& aRv) {
+  /*
+   * We throw NS_ERROR_DOM_INVALID_STATE_ERR on double unlock.
+   */
+  if (!mLocked) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  DoUnlock();
+  DetachEventListener();
+}
+
+void WakeLock::GetTopic(nsAString& aTopic) { aTopic.Assign(mTopic); }
+
+NS_IMETHODIMP
+WakeLock::HandleEvent(Event* aEvent) {
+  nsAutoString type;
+  aEvent->GetType(type);
+
+  if (type.EqualsLiteral("visibilitychange")) {
+    nsCOMPtr<Document> doc = do_QueryInterface(aEvent->GetTarget());
+    NS_ENSURE_STATE(doc);
+
+    bool oldHidden = mHidden;
+    mHidden = doc->Hidden();
+
+    if (mLocked && oldHidden != mHidden) {
+      hal::ModifyWakeLock(
+          mTopic, hal::WAKE_LOCK_NO_CHANGE,
+          mHidden ? hal::WAKE_LOCK_ADD_ONE : hal::WAKE_LOCK_REMOVE_ONE);
+    }
+
+    return NS_OK;
+  }
+
+  if (type.EqualsLiteral("pagehide")) {
+    DoUnlock();
+    return NS_OK;
+  }
+
+  if (type.EqualsLiteral("pageshow")) {
+    DoLock();
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WakeLock::Unlock() {
+  ErrorResult error;
+  Unlock(error);
+  return error.StealNSResult();
+}
+
+nsPIDOMWindowInner* WakeLock::GetParentObject() const {
+  nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(mWindow);
+  return window;
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/power/WakeLock.h b/dom/power/WakeLock.h
new file mode 100644
index 0000000000..0f14c3d7d4
--- /dev/null
+++ b/dom/power/WakeLock.h
@@ -0,0 +1,74 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_power_WakeLock_h
+#define mozilla_dom_power_WakeLock_h
+
+#include "nsCOMPtr.h"
+#include "nsIDOMEventListener.h"
+#include "nsIWakeLock.h"
+#include "nsString.h"
+#include "nsWeakReference.h"
+#include "nsWrapperCache.h"
+
+class nsPIDOMWindowInner;
+
+namespace mozilla {
+class ErrorResult;
+
+namespace dom {
+class Document;
+
+class WakeLock final : public nsIDOMEventListener,
+                       public nsSupportsWeakReference,
+                       public nsIWakeLock {
+ public:
+  NS_DECL_NSIDOMEVENTLISTENER
+  NS_DECL_NSIWAKELOCK
+
+  NS_DECL_ISUPPORTS
+
+  // Note: WakeLock lives for the lifetime of the document in order to avoid
+  // exposing GC behavior to pages. This means that
+  // |var foo = navigator.requestWakeLock('cpu'); foo = null;|
+  // doesn't unlock the 'cpu' resource.
+
+  WakeLock() = default;
+
+  // Initialize this wake lock on behalf of the given window.  Null windows are
+  // allowed; a lock without an associated window is always considered
+  // invisible.
+  nsresult Init(const nsAString& aTopic, nsPIDOMWindowInner* aWindow);
+
+  // WebIDL methods
+
+  nsPIDOMWindowInner* GetParentObject() const;
+
+  void GetTopic(nsAString& aTopic);
+
+  void Unlock(ErrorResult& aRv);
+
+ private:
+  virtual ~WakeLock();
+
+  void DoUnlock();
+  void DoLock();
+  void AttachEventListener();
+  void DetachEventListener();
+
+  bool mLocked = false;
+  bool mHidden = true;
+
+  nsString mTopic;
+
+  // window that this was created for.  Weak reference.
+  nsWeakPtr mWindow;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_power_WakeLock_h
diff --git a/dom/power/WakeLockJS.cpp b/dom/power/WakeLockJS.cpp
new file mode 100644
index 0000000000..50e4a716c0
--- /dev/null
+++ b/dom/power/WakeLockJS.cpp
@@ -0,0 +1,288 @@
+/* -*- 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 "ErrorList.h"
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Logging.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/EventTarget.h"
+#include "mozilla/dom/FeaturePolicyUtils.h"
+#include "mozilla/dom/Navigator.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WakeLockBinding.h"
+#include "mozilla/Hal.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "nsCOMPtr.h"
+#include "nsCRT.h"
+#include "nsError.h"
+#include "nsIGlobalObject.h"
+#include "nsISupports.h"
+#include "nsPIDOMWindow.h"
+#include "nsContentPermissionHelper.h"
+#include "nsServiceManagerUtils.h"
+#include "nscore.h"
+#include "WakeLock.h"
+#include "WakeLockJS.h"
+#include "WakeLockSentinel.h"
+
+namespace mozilla::dom {
+
+static mozilla::LazyLogModule sLogger("ScreenWakeLock");
+
+#define MIN_BATTERY_LEVEL 0.05
+
+nsLiteralCString WakeLockJS::GetRequestErrorMessage(RequestError aRv) {
+  switch (aRv) {
+    case RequestError::DocInactive:
+      return "The requesting document is inactive."_ns;
+    case RequestError::DocHidden:
+      return "The requesting document is hidden."_ns;
+    case RequestError::PolicyDisallowed:
+      return "A permissions policy does not allow screen-wake-lock for the requesting document."_ns;
+    case RequestError::PrefDisabled:
+      return "The pref dom.screenwakelock.enabled is disabled."_ns;
+    case RequestError::InternalFailure:
+      return "A browser-internal error occured."_ns;
+    case RequestError::PermissionDenied:
+      return "Permission to request screen-wake-lock was denied."_ns;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unknown error reason");
+      return "Unknown error"_ns;
+  }
+}
+
+// https://w3c.github.io/screen-wake-lock/#the-request-method steps 2-5
+WakeLockJS::RequestError WakeLockJS::WakeLockAllowedForDocument(
+    Document* aDoc) {
+  if (!aDoc) {
+    return RequestError::InternalFailure;
+  }
+
+  // Step 2. check policy-controlled feature screen-wake-lock
+  if (!FeaturePolicyUtils::IsFeatureAllowed(aDoc, u"screen-wake-lock"_ns)) {
+    return RequestError::PolicyDisallowed;
+  }
+
+  // Step 3. Deny wake lock for user agent specific reasons
+  if (!StaticPrefs::dom_screenwakelock_enabled()) {
+    return RequestError::PrefDisabled;
+  }
+
+  // Step 4 check doc active
+  if (!aDoc->IsActive()) {
+    return RequestError::DocInactive;
+  }
+
+  // Step 5. check doc visible
+  if (aDoc->Hidden()) {
+    return RequestError::DocHidden;
+  }
+
+  return RequestError::Success;
+}
+
+// https://w3c.github.io/screen-wake-lock/#dfn-applicable-wake-lock
+static bool IsWakeLockApplicable(WakeLockType aType) {
+  hal::BatteryInformation batteryInfo;
+  hal::GetCurrentBatteryInformation(&batteryInfo);
+  if (batteryInfo.level() <= MIN_BATTERY_LEVEL && !batteryInfo.charging()) {
+    return false;
+  }
+
+  // only currently supported wake lock type
+  return aType == WakeLockType::Screen;
+}
+
+// https://w3c.github.io/screen-wake-lock/#dfn-release-a-wake-lock
+void ReleaseWakeLock(Document* aDoc, WakeLockSentinel* aLock,
+                     WakeLockType aType) {
+  MOZ_ASSERT(aLock);
+  MOZ_ASSERT(aDoc);
+
+  RefPtr<WakeLockSentinel> kungFuDeathGrip = aLock;
+  aDoc->ActiveWakeLocks(aType).Remove(aLock);
+  aLock->NotifyLockReleased();
+  MOZ_LOG(sLogger, LogLevel::Debug, ("Released wake lock sentinel"));
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(WakeLockJS)
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(WakeLockJS)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWindow)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(WakeLockJS)
+  tmp->DetachListeners();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mWindow)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(WakeLockJS)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(WakeLockJS)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WakeLockJS)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRY(nsIDocumentActivity)
+  NS_INTERFACE_MAP_ENTRY(nsIObserver)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+NS_INTERFACE_MAP_END
+
+WakeLockJS::WakeLockJS(nsPIDOMWindowInner* aWindow) : mWindow(aWindow) {
+  AttachListeners();
+}
+
+WakeLockJS::~WakeLockJS() { DetachListeners(); }
+
+nsISupports* WakeLockJS::GetParentObject() const { return mWindow; }
+
+JSObject* WakeLockJS::WrapObject(JSContext* aCx,
+                                 JS::Handle<JSObject*> aGivenProto) {
+  return WakeLock_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+// https://w3c.github.io/screen-wake-lock/#the-request-method Step 7.3
+Result<already_AddRefed<WakeLockSentinel>, WakeLockJS::RequestError>
+WakeLockJS::Obtain(WakeLockType aType) {
+  // Step 7.3.1. check visibility again
+  nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+  if (!doc) {
+    return Err(RequestError::InternalFailure);
+  }
+  if (doc->Hidden()) {
+    return Err(RequestError::DocHidden);
+  }
+  // Step 7.3.3. let lock be a new WakeLockSentinel
+  RefPtr<WakeLockSentinel> lock =
+      MakeRefPtr<WakeLockSentinel>(mWindow->AsGlobal(), aType);
+  // Step 7.3.2. acquire a wake lock
+  if (IsWakeLockApplicable(aType)) {
+    lock->AcquireActualLock();
+  }
+
+  // Steps 7.3.4. append lock to locks
+  doc->ActiveWakeLocks(aType).Insert(lock);
+
+  return lock.forget();
+}
+
+// https://w3c.github.io/screen-wake-lock/#the-request-method
+already_AddRefed<Promise> WakeLockJS::Request(WakeLockType aType,
+                                              ErrorResult& aRv) {
+  MOZ_LOG(sLogger, LogLevel::Debug, ("Received request for wake lock"));
+  nsCOMPtr<nsIGlobalObject> global = mWindow->AsGlobal();
+
+  RefPtr<Promise> promise = Promise::Create(global, aRv);
+  NS_ENSURE_FALSE(aRv.Failed(), nullptr);
+
+  // Steps 1-5
+  nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+  RequestError rv = WakeLockAllowedForDocument(doc);
+  if (rv != RequestError::Success) {
+    promise->MaybeRejectWithNotAllowedError(GetRequestErrorMessage(rv));
+    return promise.forget();
+  }
+
+  // For now, we don't check the permission as we always grant the lock
+  // Step 7.3. Queue a task
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "ObtainWakeLock", [aType, promise, self = RefPtr<WakeLockJS>(this)]() {
+        auto lockOrErr = self->Obtain(aType);
+        if (lockOrErr.isOk()) {
+          RefPtr<WakeLockSentinel> lock = lockOrErr.unwrap();
+          promise->MaybeResolve(lock);
+          MOZ_LOG(sLogger, LogLevel::Debug,
+                  ("Resolved promise with wake lock sentinel"));
+        } else {
+          promise->MaybeRejectWithNotAllowedError(
+              GetRequestErrorMessage(lockOrErr.unwrapErr()));
+        }
+      }));
+
+  return promise.forget();
+}
+
+void WakeLockJS::AttachListeners() {
+  nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+  MOZ_ASSERT(doc);
+  DebugOnly<nsresult> rv =
+      doc->AddSystemEventListener(u"visibilitychange"_ns, this, true, false);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  doc->RegisterActivityObserver(ToSupports(this));
+
+  hal::RegisterBatteryObserver(this);
+
+  nsCOMPtr<nsIPrefBranch> prefBranch = do_GetService(NS_PREFSERVICE_CONTRACTID);
+  MOZ_ASSERT(prefBranch);
+  rv = prefBranch->AddObserver("dom.screenwakelock.enabled", this, true);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+}
+
+void WakeLockJS::DetachListeners() {
+  if (mWindow) {
+    if (nsCOMPtr<Document> doc = mWindow->GetExtantDoc()) {
+      doc->RemoveSystemEventListener(u"visibilitychange"_ns, this, true);
+
+      doc->UnregisterActivityObserver(ToSupports(this));
+    }
+  }
+
+  hal::UnregisterBatteryObserver(this);
+
+  if (nsCOMPtr<nsIPrefBranch> prefBranch =
+          do_GetService(NS_PREFSERVICE_CONTRACTID)) {
+    prefBranch->RemoveObserver("dom.screenwakelock.enabled", this);
+  }
+}
+
+NS_IMETHODIMP WakeLockJS::Observe(nsISupports* aSubject, const char* aTopic,
+                                  const char16_t* aData) {
+  if (nsCRT::strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID) == 0) {
+    if (!StaticPrefs::dom_screenwakelock_enabled()) {
+      nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+      MOZ_ASSERT(doc);
+      doc->UnlockAllWakeLocks(WakeLockType::Screen);
+    }
+  }
+  return NS_OK;
+}
+
+void WakeLockJS::NotifyOwnerDocumentActivityChanged() {
+  nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+  MOZ_ASSERT(doc);
+  if (!doc->IsActive()) {
+    doc->UnlockAllWakeLocks(WakeLockType::Screen);
+  }
+}
+
+NS_IMETHODIMP WakeLockJS::HandleEvent(Event* aEvent) {
+  nsAutoString type;
+  aEvent->GetType(type);
+
+  if (type.EqualsLiteral("visibilitychange")) {
+    nsCOMPtr<Document> doc = do_QueryInterface(aEvent->GetTarget());
+    NS_ENSURE_STATE(doc);
+
+    if (doc->Hidden()) {
+      doc->UnlockAllWakeLocks(WakeLockType::Screen);
+    }
+  }
+
+  return NS_OK;
+}
+
+void WakeLockJS::Notify(const hal::BatteryInformation& aBatteryInfo) {
+  if (aBatteryInfo.level() > MIN_BATTERY_LEVEL || aBatteryInfo.charging()) {
+    return;
+  }
+  nsCOMPtr<Document> doc = mWindow->GetExtantDoc();
+  MOZ_ASSERT(doc);
+  doc->UnlockAllWakeLocks(WakeLockType::Screen);
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/power/WakeLockJS.h b/dom/power/WakeLockJS.h
new file mode 100644
index 0000000000..c6858fdd22
--- /dev/null
+++ b/dom/power/WakeLockJS.h
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#ifndef DOM_WAKELOCKJS_H_
+#define DOM_WAKELOCKJS_H_
+
+#include "js/TypeDecls.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/HalBatteryInformation.h"
+#include "mozilla/dom/WakeLockBinding.h"
+#include "nsIDOMEventListener.h"
+#include "nsIDocumentActivity.h"
+#include "nsIObserver.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsWeakReference.h"
+#include "nsWrapperCache.h"
+
+class nsPIDOMWindowInner;
+
+namespace mozilla::dom {
+
+class Promise;
+class Document;
+class WakeLockSentinel;
+
+}  // namespace mozilla::dom
+
+namespace mozilla::dom {
+
+/**
+ * Management class for wake locks held from client scripts.
+ * Instances of this class have two purposes:
+ * - Implement navigator.wakeLock.request which creates a WakeLockSentinel
+ * - Listen for state changes that require all WakeLockSentinel to be released
+ * The WakeLockSentinel objects are held in document.mActiveLocks.
+ *
+ * https://www.w3.org/TR/screen-wake-lock/#the-wakelock-interface
+ */
+class WakeLockJS final : public nsIDOMEventListener,
+                         public nsWrapperCache,
+                         public hal::BatteryObserver,
+                         public nsIDocumentActivity,
+                         public nsIObserver,
+                         public nsSupportsWeakReference {
+ public:
+  NS_DECL_NSIDOMEVENTLISTENER
+  NS_DECL_NSIDOCUMENTACTIVITY
+  NS_DECL_NSIOBSERVER
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS_AMBIGUOUS(WakeLockJS,
+                                                        nsIDOMEventListener)
+
+ public:
+  explicit WakeLockJS(nsPIDOMWindowInner* aWindow);
+
+ protected:
+  ~WakeLockJS();
+
+ public:
+  nsISupports* GetParentObject() const;
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  void Notify(const hal::BatteryInformation& aBatteryInfo) override;
+
+  already_AddRefed<Promise> Request(WakeLockType aType, ErrorResult& aRv);
+
+ private:
+  enum class RequestError {
+    Success,
+    DocInactive,
+    DocHidden,
+    PolicyDisallowed,
+    PrefDisabled,
+    InternalFailure,
+    PermissionDenied
+  };
+
+  static nsLiteralCString GetRequestErrorMessage(RequestError aRv);
+
+  static RequestError WakeLockAllowedForDocument(Document* aDoc);
+
+  void AttachListeners();
+  void DetachListeners();
+
+  Result<already_AddRefed<WakeLockSentinel>, RequestError> Obtain(
+      WakeLockType aType);
+
+  RefPtr<nsPIDOMWindowInner> mWindow;
+};
+
+MOZ_CAN_RUN_SCRIPT
+void ReleaseWakeLock(Document* aDoc, WakeLockSentinel* aLock,
+                     WakeLockType aType);
+
+}  // namespace mozilla::dom
+
+#endif  // DOM_WAKELOCKJS_H_
diff --git a/dom/power/WakeLockSentinel.cpp b/dom/power/WakeLockSentinel.cpp
new file mode 100644
index 0000000000..1a0739dbd0
--- /dev/null
+++ b/dom/power/WakeLockSentinel.cpp
@@ -0,0 +1,100 @@
+/* -*- 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/Assertions.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TelemetryHistogramEnums.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/EventBinding.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WakeLockSentinelBinding.h"
+#include "mozilla/Hal.h"
+#include "WakeLockJS.h"
+#include "WakeLockSentinel.h"
+
+namespace mozilla::dom {
+
+JSObject* WakeLockSentinel::WrapObject(JSContext* cx,
+                                       JS::Handle<JSObject*> aGivenProto) {
+  return WakeLockSentinel_Binding::Wrap(cx, this, aGivenProto);
+}
+
+bool WakeLockSentinel::Released() const { return mReleased; }
+
+void WakeLockSentinel::NotifyLockReleased() {
+  MOZ_ASSERT(!mReleased);
+  mReleased = true;
+
+  Telemetry::AccumulateTimeDelta(Telemetry::SCREENWAKELOCK_HELD_DURATION_MS,
+                                 mCreationTime);
+
+  hal::BatteryInformation batteryInfo;
+  hal::GetCurrentBatteryInformation(&batteryInfo);
+  if (!batteryInfo.charging()) {
+    uint32_t level = static_cast<uint32_t>(100 * batteryInfo.level());
+    Telemetry::Accumulate(
+        Telemetry::SCREENWAKELOCK_RELEASE_BATTERY_LEVEL_DISCHARGING, level);
+  }
+
+  if (mHoldsActualLock) {
+    MOZ_ASSERT(mType == WakeLockType::Screen);
+    NS_DispatchToMainThread(NS_NewRunnableFunction("ReleaseWakeLock", []() {
+      hal::ModifyWakeLock(u"screen"_ns, hal::WAKE_LOCK_REMOVE_ONE,
+                          hal::WAKE_LOCK_NO_CHANGE);
+    }));
+    mHoldsActualLock = false;
+  }
+
+  EventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  RefPtr<Event> event = Event::Constructor(this, u"release"_ns, init);
+  DispatchTrustedEvent(event);
+}
+
+void WakeLockSentinel::AcquireActualLock() {
+  MOZ_ASSERT(mType == WakeLockType::Screen);
+  MOZ_ASSERT(!mHoldsActualLock);
+  mHoldsActualLock = true;
+  NS_DispatchToMainThread(NS_NewRunnableFunction("AcquireWakeLock", []() {
+    hal::ModifyWakeLock(u"screen"_ns, hal::WAKE_LOCK_ADD_ONE,
+                        hal::WAKE_LOCK_NO_CHANGE);
+  }));
+}
+
+// https://w3c.github.io/screen-wake-lock/#the-release-method
+already_AddRefed<Promise> WakeLockSentinel::ReleaseLock(ErrorResult& aRv) {
+  // ReleaseWakeLock will remove this from document.[[ActiveLocks]]
+  RefPtr<WakeLockSentinel> kungFuDeathGrip(this);
+
+  if (!mReleased) {
+    nsCOMPtr<nsIGlobalObject> global = GetOwnerGlobal();
+    if (!global) {
+      aRv.Throw(NS_ERROR_NULL_POINTER);
+      return nullptr;
+    }
+    nsCOMPtr<nsPIDOMWindowInner> window = global->GetAsInnerWindow();
+    if (!window) {
+      aRv.Throw(NS_ERROR_NULL_POINTER);
+      return nullptr;
+    }
+    nsCOMPtr<Document> doc = window->GetExtantDoc();
+    if (!doc) {
+      aRv.Throw(NS_ERROR_NULL_POINTER);
+      return nullptr;
+    }
+    ReleaseWakeLock(doc, this, mType);
+  }
+
+  if (RefPtr<Promise> p =
+          Promise::CreateResolvedWithUndefined(GetOwnerGlobal(), aRv)) {
+    return p.forget();
+  }
+  return nullptr;
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/power/WakeLockSentinel.h b/dom/power/WakeLockSentinel.h
new file mode 100644
index 0000000000..f9e79e2c65
--- /dev/null
+++ b/dom/power/WakeLockSentinel.h
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#ifndef DOM_WAKELOCKSENTINEL_H_
+#define DOM_WAKELOCKSENTINEL_H_
+
+#include "js/TypeDecls.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/dom/WakeLockBinding.h"
+
+namespace mozilla::dom {
+
+class Promise;
+
+}  // namespace mozilla::dom
+
+namespace mozilla::dom {
+
+class WakeLockSentinel final : public DOMEventTargetHelper {
+ public:
+  WakeLockSentinel(nsIGlobalObject* aOwnerWindow, WakeLockType aType)
+      : DOMEventTargetHelper(aOwnerWindow),
+        mType(aType),
+        mCreationTime(TimeStamp::Now()) {}
+
+ protected:
+  ~WakeLockSentinel() {
+    MOZ_DIAGNOSTIC_ASSERT(mReleased);
+    MOZ_DIAGNOSTIC_ASSERT(!mHoldsActualLock);
+  }
+
+ public:
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  bool Released() const;
+
+  WakeLockType Type() const { return mType; }
+
+  MOZ_CAN_RUN_SCRIPT
+  already_AddRefed<Promise> ReleaseLock(ErrorResult& aRv);
+
+  MOZ_CAN_RUN_SCRIPT
+  void NotifyLockReleased();
+
+  IMPL_EVENT_HANDLER(release);
+
+  // Acquire underlying system wake lock by modifying the HAL wake lock counter
+  void AcquireActualLock();
+
+ private:
+  WakeLockType mType;
+
+  bool mReleased = false;
+
+  /**
+   * To avoid user fingerprinting, WakeLockJS::Request will provide a
+   * WakeLockSentinel even if the lock type is not applicable or cannot be
+   * obtained.
+   * But when releasing this sentinel, we have to know whether
+   * AcquireActualLock was called.
+   *
+   * https://w3c.github.io/screen-wake-lock/#dfn-applicable-wake-lock
+   * https://w3c.github.io/screen-wake-lock/#the-request-method
+   */
+  bool mHoldsActualLock = false;
+
+  // Time when this object was created
+  TimeStamp mCreationTime;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // DOM_WAKELOCKSENTINEL_H_
diff --git a/dom/power/components.conf b/dom/power/components.conf
new file mode 100644
index 0000000000..0d09757f8d
--- /dev/null
+++ b/dom/power/components.conf
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+Classes = [
+    {
+        'cid': '{18c2e238-3a0a-4153-89fc-166b3b1465a1}',
+        'contract_ids': ['@mozilla.org/power/powermanagerservice;1'],
+        'type': 'mozilla::dom::power::PowerManagerService',
+        'constructor': 'mozilla::dom::power::PowerManagerService::GetInstance',
+        'headers': ['mozilla/dom/power/PowerManagerService.h'],
+        'singleton': True,
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_AND_SOCKET_PROCESS,
+    },
+]
diff --git a/dom/power/moz.build b/dom/power/moz.build
new file mode 100644
index 0000000000..5f04a3247d
--- /dev/null
+++ b/dom/power/moz.build
@@ -0,0 +1,39 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "DOM: Core & HTML")
+
+XPIDL_SOURCES += [
+    "nsIDOMWakeLockListener.idl",
+    "nsIPowerManagerService.idl",
+    "nsIWakeLock.idl",
+]
+
+XPIDL_MODULE = "dom_power"
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+EXPORTS.mozilla.dom += ["WakeLock.h", "WakeLockJS.h", "WakeLockSentinel.h"]
+
+EXPORTS.mozilla.dom.power += [
+    "PowerManagerService.h",
+]
+
+UNIFIED_SOURCES += [
+    "PowerManagerService.cpp",
+    "WakeLock.cpp",
+    "WakeLockJS.cpp",
+    "WakeLockSentinel.cpp",
+]
+
+MOCHITEST_MANIFESTS += ["tests/mochitest.toml"]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
diff --git a/dom/power/nsIDOMWakeLockListener.idl b/dom/power/nsIDOMWakeLockListener.idl
new file mode 100644
index 0000000000..366e9cf594
--- /dev/null
+++ b/dom/power/nsIDOMWakeLockListener.idl
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsISupports.idl"
+
+[scriptable, function, uuid(4e258af8-cffb-47bc-b16d-e8241243426e)]
+interface nsIDOMMozWakeLockListener : nsISupports
+{
+  /**
+   * The callback will be called when a lock topic changes its lock
+   * state.
+   *
+   * Possible states are:
+   *
+   *  - "unlocked" - nobody holds the wake lock.
+   *
+   *  - "locked-foreground" - at least one window holds the wake lock,
+   *    and it is visible.
+   *
+   *  - "locked-background" - at least one window holds the wake lock,
+   *    but all of them are hidden.
+   *
+   * @param aTopic The resource name related to the wake lock.
+   * @param aState The wake lock state
+   */
+  void callback(in AString aTopic, in AString aState);
+};
diff --git a/dom/power/nsIPowerManagerService.idl b/dom/power/nsIPowerManagerService.idl
new file mode 100644
index 0000000000..3fef3de9a3
--- /dev/null
+++ b/dom/power/nsIPowerManagerService.idl
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+
+%{C++
+#define POWERMANAGERSERVICE_CONTRACTID "@mozilla.org/power/powermanagerservice;1"
+%}
+
+interface nsIDOMMozWakeLockListener;
+interface mozIDOMWindow;
+interface nsIWakeLock;
+
+/**
+ * For use with non-content code.
+ */
+[scriptable, builtinclass, uuid(ba7ca4c1-9d92-4425-a83b-85dd7fa953f7)]
+interface nsIPowerManagerService : nsISupports
+{
+  void              addWakeLockListener(in nsIDOMMozWakeLockListener aListener);
+  void              removeWakeLockListener(in nsIDOMMozWakeLockListener aListener);
+  AString           getWakeLockState(in AString aTopic);
+
+  /**
+   * Return a wake lock (MozWakeLock) object of aTopic associated with aWindow.
+   * A wake lock without associated window, e.g. used in chrome, is
+   * always considered invisible.
+   */
+  nsIWakeLock newWakeLock(in AString aTopic, [optional] in mozIDOMWindow aWindow);
+};
diff --git a/dom/power/nsIWakeLock.idl b/dom/power/nsIWakeLock.idl
new file mode 100644
index 0000000000..5ebc158109
--- /dev/null
+++ b/dom/power/nsIWakeLock.idl
@@ -0,0 +1,12 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsISupports.idl"
+
+[scriptable, builtinclass, uuid(e27e57ce-fa63-4035-b9ef-27c5dc0cc3ae)]
+interface nsIWakeLock : nsISupports
+{
+  void unlock();
+};
diff --git a/dom/power/tests/mochitest.toml b/dom/power/tests/mochitest.toml
new file mode 100644
index 0000000000..0b57119a8a
--- /dev/null
+++ b/dom/power/tests/mochitest.toml
@@ -0,0 +1,9 @@
+[DEFAULT]
+prefs = ["dom.screenwakelock.enabled=true"]
+scheme = "https"
+
+["test_dynamic_pref_change.html"]
+fail-if = ["xorigin"]  # cross-origin use requires permissions policy
+
+["test_wakelock_default_permission.html"]
+fail-if = ["xorigin"]  # cross-origin use requires permissions policy
diff --git a/dom/power/tests/test_dynamic_pref_change.html b/dom/power/tests/test_dynamic_pref_change.html
new file mode 100644
index 0000000000..c6aba76246
--- /dev/null
+++ b/dom/power/tests/test_dynamic_pref_change.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test Screen Wake Lock responds to dynamic pref changes</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+    /* globals SpecialPowers */
+    'use strict';
+
+    function spinEventLoop() {
+        return new Promise(resolve => {
+            setTimeout(resolve, 0);
+        });
+    }
+
+    add_task(async function my_test() {
+      const lock = await navigator.wakeLock.request("screen");
+      await SpecialPowers.pushPrefEnv({
+        set: [["dom.screenwakelock.enabled", false]],
+      });
+      await spinEventLoop();
+      ok(lock.released, "Lock was released once pref was deactivated");
+      await SpecialPowers.popPrefEnv();
+    });
+  </script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+</body>
+</html>
diff --git a/dom/power/tests/test_wakelock_default_permission.html b/dom/power/tests/test_wakelock_default_permission.html
new file mode 100644
index 0000000000..78065f6eeb
--- /dev/null
+++ b/dom/power/tests/test_wakelock_default_permission.html
@@ -0,0 +1,20 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test Screen Wake Lock Permission Granted by Default</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+  <script>
+    add_task(async function my_test() {
+      const status = await navigator.permissions.query({name:'screen-wake-lock'});
+      is(status.state, "granted", "Permission is granted by default");
+    });
+  </script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+</body>
+</html>