Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 922 insertions, 0 deletions

diff --git a/dom/webscheduling/TaskSignal.h b/dom/webscheduling/TaskSignal.h
new file mode 100644
index 0000000000..2cc02cc2fc
--- /dev/null
+++ b/dom/webscheduling/TaskSignal.h
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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/. */
+
+#ifndef mozilla_dom_TaskSignal_h
+#define mozilla_dom_TaskSignal_h
+
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/dom/AbortSignal.h"
+#include "mozilla/dom/WebTaskSchedulingBinding.h"
+#include "WebTaskScheduler.h"
+
+namespace mozilla::dom {
+class TaskSignal : public AbortSignal {
+ public:
+  TaskSignal(nsIGlobalObject* aGlobal, TaskPriority aPriority)
+      : AbortSignal(aGlobal, false, JS::UndefinedHandleValue),
+        mPriority(aPriority),
+        mPriorityChanging(false) {}
+
+  IMPL_EVENT_HANDLER(prioritychange);
+
+  TaskPriority Priority() const { return mPriority; }
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override {
+    return TaskSignal_Binding::Wrap(aCx, this, aGivenProto);
+  }
+
+  void SetPriority(TaskPriority aPriority) { mPriority = aPriority; }
+
+  bool IsTaskSignal() const override { return true; }
+
+  bool PriorityChanging() const { return mPriorityChanging; }
+
+  void SetPriorityChanging(bool aPriorityChanging) {
+    mPriorityChanging = aPriorityChanging;
+  }
+
+  void SetWebTaskScheduler(WebTaskScheduler* aScheduler) {
+    mSchedulers.AppendElement(aScheduler);
+  }
+
+  void RunPriorityChangeAlgorithms() {
+    for (const WeakPtr<WebTaskScheduler>& scheduler : mSchedulers) {
+      scheduler->RunTaskSignalPriorityChange(this);
+    }
+  }
+
+ private:
+  TaskPriority mPriority;
+
+  bool mPriorityChanging;
+
+  nsTArray<WeakPtr<WebTaskScheduler>> mSchedulers;
+
+  ~TaskSignal() = default;
+};
+}  // namespace mozilla::dom
+#endif
diff --git a/dom/webscheduling/WebTaskController.cpp b/dom/webscheduling/WebTaskController.cpp
new file mode 100644
index 0000000000..f9d27aaa0d
--- /dev/null
+++ b/dom/webscheduling/WebTaskController.cpp
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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 "WebTaskController.h"
+#include "TaskSignal.h"
+
+#include "mozilla/dom/TaskPriorityChangeEvent.h"
+
+namespace mozilla::dom {
+
+WebTaskController::WebTaskController(nsIGlobalObject* aGlobal,
+                                     TaskPriority aPriority)
+    : AbortController(aGlobal) {
+  MOZ_ASSERT(!mSignal);
+  mSignal = new TaskSignal(aGlobal, aPriority);
+}
+
+void WebTaskController::SetPriority(TaskPriority aPriority, ErrorResult& aRv) {
+  // https://wicg.github.io/scheduling-apis/#tasksignal-signal-priority-change
+  RefPtr<TaskSignal> taskSignal = static_cast<TaskSignal*>(mSignal.get());
+  MOZ_ASSERT(taskSignal);
+  if (taskSignal->PriorityChanging()) {
+    aRv.ThrowNotAllowedError("Signal's priority changing is true");
+    return;
+  }
+
+  if (taskSignal->Priority() == aPriority) {
+    return;
+  }
+
+  taskSignal->SetPriorityChanging(true);
+
+  TaskPriority previousPriority = taskSignal->Priority();
+  taskSignal->SetPriority(aPriority);
+
+  taskSignal->RunPriorityChangeAlgorithms();
+
+  TaskPriorityChangeEventInit init;
+  init.mPreviousPriority = previousPriority;
+  RefPtr<TaskPriorityChangeEvent> event = TaskPriorityChangeEvent::Constructor(
+      taskSignal, u"prioritychange"_ns, init);
+
+  event->SetTrusted(true);
+
+  taskSignal->DispatchEvent(*event);
+  taskSignal->SetPriorityChanging(false);
+}
+
+already_AddRefed<WebTaskController> WebTaskController::Constructor(
+    const GlobalObject& aGlobal, const TaskControllerInit& aInit,
+    ErrorResult& aRv) {
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+  if (!global) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+  RefPtr<WebTaskController> webTaskController =
+      new WebTaskController(global, aInit.mPriority);
+  return webTaskController.forget();
+}
+
+JSObject* WebTaskController::WrapObject(JSContext* aCx,
+                                        JS::Handle<JSObject*> aGivenProto) {
+  return TaskController_Binding::Wrap(aCx, this, aGivenProto);
+}
+}  // namespace mozilla::dom
diff --git a/dom/webscheduling/WebTaskController.h b/dom/webscheduling/WebTaskController.h
new file mode 100644
index 0000000000..ade3526531
--- /dev/null
+++ b/dom/webscheduling/WebTaskController.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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/. */
+
+#ifndef mozilla_dom_WebTaskController_h
+#define mozilla_dom_WebTaskController_h
+
+#include "nsWrapperCache.h"
+
+#include "mozilla/dom/WebTaskSchedulingBinding.h"
+#include "mozilla/dom/AbortController.h"
+
+namespace mozilla::dom {
+class WebTaskController : public AbortController {
+ public:
+  explicit WebTaskController(nsIGlobalObject* aGlobal, TaskPriority aPriority);
+
+  static already_AddRefed<WebTaskController> Constructor(
+      const GlobalObject& aGlobal, const TaskControllerInit& aInit,
+      ErrorResult& aRv);
+
+  virtual JSObject* WrapObject(JSContext* aCx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  void SetPriority(TaskPriority aPriority, ErrorResult& aRv);
+
+ private:
+  ~WebTaskController() = default;
+};
+}  // namespace mozilla::dom
+
+#endif
diff --git a/dom/webscheduling/WebTaskScheduler.cpp b/dom/webscheduling/WebTaskScheduler.cpp
new file mode 100644
index 0000000000..14cc51ba66
--- /dev/null
+++ b/dom/webscheduling/WebTaskScheduler.cpp
@@ -0,0 +1,354 @@
+/* -*- 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 "nsTHashMap.h"
+#include "WebTaskScheduler.h"
+#include "WebTaskSchedulerWorker.h"
+#include "WebTaskSchedulerMainThread.h"
+#include "TaskSignal.h"
+#include "nsGlobalWindowInner.h"
+
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/TimeoutManager.h"
+
+namespace mozilla::dom {
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback, WebTaskQueue& aQueue,
+    const char* aName, uint32_t aFlags = 0) {
+  ImplCycleCollectionTraverse(aCallback, aQueue.Tasks(), aName, aFlags);
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(WebTask)
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(WebTask)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallback)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPromise)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(WebTask)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCallback)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPromise)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_PTR
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(WebTask)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(WebTask)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WebTask)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTION(DelayedWebTaskHandler)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DelayedWebTaskHandler)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(DelayedWebTaskHandler)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(DelayedWebTaskHandler)
+
+void WebTask::RunAbortAlgorithm() {
+  // no-op if WebTask::Run has been called already
+  if (mPromise->State() == Promise::PromiseState::Pending) {
+    // There are two things that can keep a WebTask alive, either the abort
+    // signal or WebTaskQueue.
+    // It's possible that this task get cleared out from the WebTaskQueue first,
+    // and then the abort signal get aborted. For example, the callback function
+    // was async and there's a signal.abort() call in the callback.
+    if (isInList()) {
+      remove();
+    }
+
+    AutoJSAPI jsapi;
+    if (!jsapi.Init(mPromise->GetGlobalObject())) {
+      mPromise->MaybeReject(NS_ERROR_UNEXPECTED);
+    } else {
+      JSContext* cx = jsapi.cx();
+      JS::Rooted<JS::Value> reason(cx);
+      Signal()->GetReason(cx, &reason);
+      mPromise->MaybeReject(reason);
+    }
+  }
+
+  MOZ_ASSERT(!isInList());
+}
+
+bool WebTask::Run() {
+  MOZ_ASSERT(HasScheduled());
+  remove();
+
+  ErrorResult error;
+
+  nsIGlobalObject* global = mPromise->GetGlobalObject();
+  if (!global || global->IsDying()) {
+    return false;
+  }
+
+  AutoJSAPI jsapi;
+  if (!jsapi.Init(global)) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> returnVal(jsapi.cx());
+
+  MOZ_ASSERT(mPromise->State() == Promise::PromiseState::Pending);
+
+  MOZ_KnownLive(mCallback)->Call(&returnVal, error, "WebTask",
+                                 CallbackFunction::eRethrowExceptions);
+
+  error.WouldReportJSException();
+
+#ifdef DEBUG
+  Promise::PromiseState promiseState = mPromise->State();
+
+  // If the state is Rejected, it means the above Call triggers the
+  // RunAbortAlgorithm method and rejected the promise
+  MOZ_ASSERT_IF(promiseState != Promise::PromiseState::Pending,
+                promiseState == Promise::PromiseState::Rejected);
+#endif
+
+  if (error.Failed()) {
+    if (!error.IsUncatchableException()) {
+      mPromise->MaybeReject(std::move(error));
+    } else {
+      error.SuppressException();
+    }
+  } else {
+    mPromise->MaybeResolve(returnVal);
+  }
+
+  MOZ_ASSERT(!isInList());
+  return true;
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(WebTaskScheduler, mParent,
+                                      mStaticPriorityTaskQueues,
+                                      mDynamicPriorityTaskQueues)
+
+/* static */
+already_AddRefed<WebTaskSchedulerMainThread>
+WebTaskScheduler::CreateForMainThread(nsGlobalWindowInner* aWindow) {
+  RefPtr<WebTaskSchedulerMainThread> scheduler =
+      new WebTaskSchedulerMainThread(aWindow->AsGlobal());
+  return scheduler.forget();
+}
+
+already_AddRefed<WebTaskSchedulerWorker> WebTaskScheduler::CreateForWorker(
+    WorkerPrivate* aWorkerPrivate) {
+  aWorkerPrivate->AssertIsOnWorkerThread();
+  RefPtr<WebTaskSchedulerWorker> scheduler =
+      new WebTaskSchedulerWorker(aWorkerPrivate);
+  return scheduler.forget();
+}
+
+WebTaskScheduler::WebTaskScheduler(nsIGlobalObject* aParent)
+    : mParent(aParent), mNextEnqueueOrder(1) {
+  MOZ_ASSERT(aParent);
+}
+
+JSObject* WebTaskScheduler::WrapObject(JSContext* cx,
+                                       JS::Handle<JSObject*> aGivenProto) {
+  return Scheduler_Binding::Wrap(cx, this, aGivenProto);
+}
+
+already_AddRefed<Promise> WebTaskScheduler::PostTask(
+    SchedulerPostTaskCallback& aCallback,
+    const SchedulerPostTaskOptions& aOptions) {
+  const Optional<OwningNonNull<AbortSignal>>& taskSignal = aOptions.mSignal;
+  const Optional<TaskPriority>& taskPriority = aOptions.mPriority;
+
+  ErrorResult rv;
+  // Instead of making WebTaskScheduler::PostTask throws, we always
+  // create the promise and return it. This is because we need to
+  // create the promise explicitly to be able to reject it with
+  // signal's reason.
+  RefPtr<Promise> promise = Promise::Create(mParent, rv);
+  if (rv.Failed()) {
+    return nullptr;
+  }
+
+  nsIGlobalObject* global = GetParentObject();
+  if (!global || global->IsDying()) {
+    promise->MaybeRejectWithNotSupportedError("Current window is detached");
+    return promise.forget();
+  }
+
+  if (taskSignal.WasPassed()) {
+    AbortSignal& signalValue = taskSignal.Value();
+
+    if (signalValue.Aborted()) {
+      AutoJSAPI jsapi;
+      if (!jsapi.Init(global)) {
+        promise->MaybeReject(NS_ERROR_UNEXPECTED);
+        return promise.forget();
+      }
+
+      JSContext* cx = jsapi.cx();
+      JS::Rooted<JS::Value> reason(cx);
+      signalValue.GetReason(cx, &reason);
+      promise->MaybeReject(reason);
+      return promise.forget();
+    }
+  }
+
+  // Let queue be the result of selecting the scheduler task queue for scheduler
+  // given signal and priority.
+  WebTaskQueue& taskQueue = SelectTaskQueue(taskSignal, taskPriority);
+
+  uint64_t delay = aOptions.mDelay;
+
+  RefPtr<WebTask> task = CreateTask(taskQueue, taskSignal, aCallback, promise);
+  if (delay > 0) {
+    nsresult rv = SetTimeoutForDelayedTask(task, delay);
+    if (NS_FAILED(rv)) {
+      promise->MaybeRejectWithUnknownError(
+          "Failed to setup timeout for delayed task");
+    }
+    return promise.forget();
+  }
+
+  if (!QueueTask(task)) {
+    MOZ_ASSERT(task->isInList());
+    task->remove();
+
+    promise->MaybeRejectWithNotSupportedError("Unable to queue the task");
+    return promise.forget();
+  }
+
+  return promise.forget();
+}
+
+already_AddRefed<WebTask> WebTaskScheduler::CreateTask(
+    WebTaskQueue& aQueue, const Optional<OwningNonNull<AbortSignal>>& aSignal,
+    SchedulerPostTaskCallback& aCallback, Promise* aPromise) {
+  uint32_t nextEnqueueOrder = mNextEnqueueOrder;
+  ++mNextEnqueueOrder;
+
+  RefPtr<WebTask> task = new WebTask(nextEnqueueOrder, aCallback, aPromise);
+
+  aQueue.AddTask(task);
+
+  if (aSignal.WasPassed()) {
+    AbortSignal& signalValue = aSignal.Value();
+    task->Follow(&signalValue);
+  }
+
+  return task.forget();
+}
+
+bool WebTaskScheduler::QueueTask(WebTask* aTask) {
+  if (!DispatchEventLoopRunnable()) {
+    return false;
+  }
+  MOZ_ASSERT(!aTask->HasScheduled());
+  aTask->SetHasScheduled(true);
+  return true;
+}
+
+WebTask* WebTaskScheduler::GetNextTask() const {
+  // We first combine queues from both mStaticPriorityTaskQueues and
+  // mDynamicPriorityTaskQueues into a single hash map which the
+  // keys are the priorities and the values are all the queues that
+  // belong to this priority.
+  //
+  // Then From the queues which
+  //   1. Have scheduled tasks
+  //   2. Its priority is not less than any other queues' priority
+  // We pick the task which has the smallest enqueue order.
+  nsTHashMap<nsUint32HashKey, nsTArray<WebTaskQueue*>> allQueues;
+
+  for (auto iter = mStaticPriorityTaskQueues.ConstIter(); !iter.Done();
+       iter.Next()) {
+    const auto& queue = iter.Data();
+    if (!queue->Tasks().isEmpty() && queue->GetFirstScheduledTask()) {
+      nsTArray<WebTaskQueue*>& queuesForThisPriority =
+          allQueues.LookupOrInsert(static_cast<uint32_t>(iter.Key()));
+      queuesForThisPriority.AppendElement(queue.get());
+    }
+  }
+
+  for (auto iter = mDynamicPriorityTaskQueues.ConstIter(); !iter.Done();
+       iter.Next()) {
+    const auto& queue = iter.Data();
+    if (!queue->Tasks().isEmpty() && queue->GetFirstScheduledTask()) {
+      nsTArray<WebTaskQueue*>& queuesForThisPriority = allQueues.LookupOrInsert(
+          static_cast<uint32_t>(iter.Key()->Priority()));
+      queuesForThisPriority.AppendElement(queue.get());
+    }
+  }
+
+  if (allQueues.IsEmpty()) {
+    return nullptr;
+  }
+
+  for (uint32_t priority = static_cast<uint32_t>(TaskPriority::User_blocking);
+       priority < static_cast<uint32_t>(TaskPriority::EndGuard_); ++priority) {
+    if (auto queues = allQueues.Lookup(priority)) {
+      WebTaskQueue* oldestQueue = nullptr;
+      MOZ_ASSERT(!queues.Data().IsEmpty());
+      for (auto& webTaskQueue : queues.Data()) {
+        MOZ_ASSERT(webTaskQueue->GetFirstScheduledTask());
+        if (!oldestQueue) {
+          oldestQueue = webTaskQueue;
+        } else {
+          WebTask* firstScheduledRunnableForCurrentQueue =
+              webTaskQueue->GetFirstScheduledTask();
+          WebTask* firstScheduledRunnableForOldQueue =
+              oldestQueue->GetFirstScheduledTask();
+          if (firstScheduledRunnableForOldQueue->EnqueueOrder() >
+              firstScheduledRunnableForCurrentQueue->EnqueueOrder()) {
+            oldestQueue = webTaskQueue;
+          }
+        }
+      }
+      MOZ_ASSERT(oldestQueue);
+      return oldestQueue->GetFirstScheduledTask();
+    }
+  }
+  return nullptr;
+}
+
+void WebTaskScheduler::Disconnect() {
+  mStaticPriorityTaskQueues.Clear();
+  mDynamicPriorityTaskQueues.Clear();
+}
+
+void WebTaskScheduler::RunTaskSignalPriorityChange(TaskSignal* aTaskSignal) {
+  WebTaskQueue* const taskQueue = mDynamicPriorityTaskQueues.Get(aTaskSignal);
+  MOZ_ASSERT(taskQueue);
+  taskQueue->SetPriority(aTaskSignal->Priority());
+}
+
+WebTaskQueue& WebTaskScheduler::SelectTaskQueue(
+    const Optional<OwningNonNull<AbortSignal>>& aSignal,
+    const Optional<TaskPriority>& aPriority) {
+  bool useSignal = !aPriority.WasPassed() && aSignal.WasPassed() &&
+                   aSignal.Value().IsTaskSignal();
+
+  if (useSignal) {
+    TaskSignal* taskSignal = static_cast<TaskSignal*>(&(aSignal.Value()));
+    WebTaskQueue* const taskQueue =
+        mDynamicPriorityTaskQueues.GetOrInsertNew(taskSignal);
+    taskQueue->SetPriority(taskSignal->Priority());
+    taskSignal->SetWebTaskScheduler(this);
+    MOZ_ASSERT(mDynamicPriorityTaskQueues.Contains(taskSignal));
+
+    return *taskQueue;
+  }
+
+  TaskPriority taskPriority =
+      aPriority.WasPassed() ? aPriority.Value() : TaskPriority::User_visible;
+
+  WebTaskQueue* const taskQueue = mStaticPriorityTaskQueues.GetOrInsertNew(
+      static_cast<uint32_t>(taskPriority));
+  taskQueue->SetPriority(taskPriority);
+  MOZ_ASSERT(
+      mStaticPriorityTaskQueues.Contains(static_cast<uint32_t>(taskPriority)));
+  return *taskQueue;
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/webscheduling/WebTaskScheduler.h b/dom/webscheduling/WebTaskScheduler.h
new file mode 100644
index 0000000000..fcddd09d36
--- /dev/null
+++ b/dom/webscheduling/WebTaskScheduler.h
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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/. */
+
+#ifndef mozilla_dom_WebTaskScheduler_h
+#define mozilla_dom_WebTaskScheduler_h
+
+#include "nsThreadUtils.h"
+#include "nsPIDOMWindow.h"
+#include "nsWrapperCache.h"
+#include "nsClassHashtable.h"
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/AbortFollower.h"
+#include "mozilla/dom/TimeoutHandler.h"
+#include "mozilla/dom/WebTaskSchedulingBinding.h"
+
+namespace mozilla::dom {
+class WebTask : public LinkedListElement<RefPtr<WebTask>>,
+                public AbortFollower,
+                public SupportsWeakPtr {
+  friend class WebTaskScheduler;
+
+ public:
+  MOZ_CAN_RUN_SCRIPT bool Run();
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+
+  NS_DECL_CYCLE_COLLECTION_CLASS(WebTask)
+  WebTask(uint32_t aEnqueueOrder, SchedulerPostTaskCallback& aCallback,
+          Promise* aPromise)
+      : mEnqueueOrder(aEnqueueOrder),
+        mCallback(&aCallback),
+        mPromise(aPromise),
+        mHasScheduled(false) {}
+
+  void RunAbortAlgorithm() override;
+
+  bool HasScheduled() const { return mHasScheduled; }
+
+  uint32_t EnqueueOrder() const { return mEnqueueOrder; }
+
+ private:
+  void SetHasScheduled(bool aHasScheduled) { mHasScheduled = aHasScheduled; }
+
+  uint32_t mEnqueueOrder;
+
+  RefPtr<SchedulerPostTaskCallback> mCallback;
+  RefPtr<Promise> mPromise;
+
+  bool mHasScheduled;
+
+  ~WebTask() = default;
+};
+
+class WebTaskQueue {
+ public:
+  WebTaskQueue() = default;
+
+  TaskPriority Priority() const { return mPriority; }
+  void SetPriority(TaskPriority aNewPriority) { mPriority = aNewPriority; }
+
+  LinkedList<RefPtr<WebTask>>& Tasks() { return mTasks; }
+
+  void AddTask(WebTask* aTask) { mTasks.insertBack(aTask); }
+
+  // TODO: To optimize it, we could have the scheduled and unscheduled
+  // tasks stored separately.
+  WebTask* GetFirstScheduledTask() {
+    for (const auto& task : mTasks) {
+      if (task->HasScheduled()) {
+        return task;
+      }
+    }
+    return nullptr;
+  }
+
+  ~WebTaskQueue() { mTasks.clear(); }
+
+ private:
+  TaskPriority mPriority = TaskPriority::User_visible;
+  LinkedList<RefPtr<WebTask>> mTasks;
+};
+
+class WebTaskSchedulerMainThread;
+class WebTaskSchedulerWorker;
+
+class WebTaskScheduler : public nsWrapperCache, public SupportsWeakPtr {
+  friend class DelayedWebTaskHandler;
+
+ public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(WebTaskScheduler)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_WRAPPERCACHE_CLASS(WebTaskScheduler)
+
+  static already_AddRefed<WebTaskSchedulerMainThread> CreateForMainThread(
+      nsGlobalWindowInner* aWindow);
+
+  static already_AddRefed<WebTaskSchedulerWorker> CreateForWorker(
+      WorkerPrivate* aWorkerPrivate);
+
+  explicit WebTaskScheduler(nsIGlobalObject* aParent);
+
+  already_AddRefed<Promise> PostTask(SchedulerPostTaskCallback& aCallback,
+                                     const SchedulerPostTaskOptions& aOptions);
+
+  nsIGlobalObject* GetParentObject() const { return mParent; }
+
+  virtual JSObject* WrapObject(JSContext* cx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  WebTask* GetNextTask() const;
+
+  void Disconnect();
+
+  void RunTaskSignalPriorityChange(TaskSignal* aTaskSignal);
+
+ protected:
+  virtual ~WebTaskScheduler() = default;
+  nsCOMPtr<nsIGlobalObject> mParent;
+
+  uint32_t mNextEnqueueOrder;
+
+ private:
+  already_AddRefed<WebTask> CreateTask(
+      WebTaskQueue& aQueue, const Optional<OwningNonNull<AbortSignal>>& aSignal,
+      SchedulerPostTaskCallback& aCallback, Promise* aPromise);
+
+  bool QueueTask(WebTask* aTask);
+
+  WebTaskQueue& SelectTaskQueue(
+      const Optional<OwningNonNull<AbortSignal>>& aSignal,
+      const Optional<TaskPriority>& aPriority);
+
+  virtual nsresult SetTimeoutForDelayedTask(WebTask* aTask,
+                                            uint64_t aDelay) = 0;
+  virtual bool DispatchEventLoopRunnable() = 0;
+
+  nsClassHashtable<nsUint32HashKey, WebTaskQueue> mStaticPriorityTaskQueues;
+  nsClassHashtable<nsPtrHashKey<TaskSignal>, WebTaskQueue>
+      mDynamicPriorityTaskQueues;
+};
+
+class DelayedWebTaskHandler final : public TimeoutHandler {
+ public:
+  DelayedWebTaskHandler(JSContext* aCx, WebTaskScheduler* aScheduler,
+                        WebTask* aTask)
+      : TimeoutHandler(aCx), mScheduler(aScheduler), mWebTask(aTask) {}
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(DelayedWebTaskHandler)
+
+  MOZ_CAN_RUN_SCRIPT bool Call(const char* /* unused */) override {
+    if (mScheduler && mWebTask) {
+      MOZ_ASSERT(!mWebTask->HasScheduled());
+      if (!mScheduler->QueueTask(mWebTask)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+ private:
+  ~DelayedWebTaskHandler() override = default;
+  WeakPtr<WebTaskScheduler> mScheduler;
+  // WebTask gets added to WebTaskQueue, and WebTaskQueue keeps its alive.
+  WeakPtr<WebTask> mWebTask;
+};
+}  // namespace mozilla::dom
+#endif
diff --git a/dom/webscheduling/WebTaskSchedulerMainThread.cpp b/dom/webscheduling/WebTaskSchedulerMainThread.cpp
new file mode 100644
index 0000000000..ed06fd0f0a
--- /dev/null
+++ b/dom/webscheduling/WebTaskSchedulerMainThread.cpp
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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 "mozilla/TaskController.h"
+#include "mozilla/dom/TimeoutManager.h"
+
+#include "nsContentUtils.h"
+#include "WebTaskSchedulerMainThread.h"
+
+namespace mozilla::dom {
+
+NS_IMETHODIMP WebTaskMainThreadRunnable::Run() {
+  if (mScheduler) {
+    RefPtr<WebTask> task = mScheduler->GetNextTask();
+    if (task) {
+      task->Run();
+    }
+  }
+  return NS_OK;
+}
+
+nsresult WebTaskSchedulerMainThread::SetTimeoutForDelayedTask(WebTask* aTask,
+                                                              uint64_t aDelay) {
+  JSContext* cx = nsContentUtils::GetCurrentJSContext();
+  if (!cx) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  nsIGlobalObject* global = GetParentObject();
+  MOZ_ASSERT(global);
+
+  RefPtr<DelayedWebTaskHandler> handler =
+      new DelayedWebTaskHandler(cx, this, aTask);
+
+  int32_t delay = aDelay > INT32_MAX ? INT32_MAX : (int32_t)aDelay;
+
+  int32_t handle;
+  return global->AsInnerWindow()->TimeoutManager().SetTimeout(
+      handler, delay, /* aIsInterval */ false,
+      Timeout::Reason::eDelayedWebTaskTimeout, &handle);
+}
+
+bool WebTaskSchedulerMainThread::DispatchEventLoopRunnable() {
+  RefPtr<WebTaskMainThreadRunnable> runnable =
+      new WebTaskMainThreadRunnable(this);
+
+  MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThreadQueue(runnable.forget(),
+                                                   EventQueuePriority::Normal));
+  return true;
+}
+}  // namespace mozilla::dom
diff --git a/dom/webscheduling/WebTaskSchedulerMainThread.h b/dom/webscheduling/WebTaskSchedulerMainThread.h
new file mode 100644
index 0000000000..a5d57f6228
--- /dev/null
+++ b/dom/webscheduling/WebTaskSchedulerMainThread.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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/. */
+
+#ifndef mozilla_dom_WebSchedulerMainThread_h
+#define mozilla_dom_WebSchedulerMainThread_h
+
+#include "WebTaskScheduler.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsThreadUtils.h"
+
+#include "mozilla/dom/AbortFollower.h"
+
+namespace mozilla::dom {
+class WebTaskMainThreadRunnable final : public Runnable {
+ public:
+  explicit WebTaskMainThreadRunnable(WebTaskSchedulerMainThread* aScheduler)
+      : Runnable("WebTaskMainThreadRunnable"), mScheduler(aScheduler) {}
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHOD Run() override;
+
+ private:
+  ~WebTaskMainThreadRunnable() = default;
+  WeakPtr<WebTaskSchedulerMainThread> mScheduler;
+};
+
+class WebTaskSchedulerMainThread final : public WebTaskScheduler {
+ public:
+  explicit WebTaskSchedulerMainThread(nsIGlobalObject* aParent)
+      : WebTaskScheduler(aParent) {}
+
+ private:
+  nsresult SetTimeoutForDelayedTask(WebTask* aTask, uint64_t aDelay) override;
+  bool DispatchEventLoopRunnable() override;
+
+  ~WebTaskSchedulerMainThread() = default;
+};
+}  // namespace mozilla::dom
+#endif
diff --git a/dom/webscheduling/WebTaskSchedulerWorker.cpp b/dom/webscheduling/WebTaskSchedulerWorker.cpp
new file mode 100644
index 0000000000..89fbb6169f
--- /dev/null
+++ b/dom/webscheduling/WebTaskSchedulerWorker.cpp
@@ -0,0 +1,59 @@
+/* -*- 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 "WebTaskSchedulerWorker.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/dom/TimeoutManager.h"
+
+namespace mozilla::dom {
+
+WebTaskWorkerRunnable::WebTaskWorkerRunnable(
+    WorkerPrivate* aWorkerPrivate, WebTaskSchedulerWorker* aSchedulerWorker)
+    : WorkerSameThreadRunnable(aWorkerPrivate),
+      mSchedulerWorker(aSchedulerWorker) {
+  MOZ_ASSERT(mSchedulerWorker);
+}
+
+WebTaskSchedulerWorker::WebTaskSchedulerWorker(WorkerPrivate* aWorkerPrivate)
+    : WebTaskScheduler(aWorkerPrivate->GlobalScope()),
+      mWorkerPrivate(aWorkerPrivate) {}
+
+bool WebTaskWorkerRunnable::WorkerRun(JSContext* aCx,
+                                      WorkerPrivate* aWorkerPrivate) {
+  aWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mSchedulerWorker) {
+    RefPtr<WebTask> task = mSchedulerWorker->GetNextTask();
+    if (task) {
+      task->Run();
+    }
+  }
+  return true;
+}
+
+nsresult WebTaskSchedulerWorker::SetTimeoutForDelayedTask(WebTask* aTask,
+                                                          uint64_t aDelay) {
+  JSContext* cx = nsContentUtils::GetCurrentJSContext();
+  if (!cx) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  RefPtr<DelayedWebTaskHandler> handler =
+      new DelayedWebTaskHandler(cx, this, aTask);
+  ErrorResult rv;
+
+  int32_t delay = aDelay > INT32_MAX ? INT32_MAX : (int32_t)aDelay;
+  mWorkerPrivate->SetTimeout(cx, handler, delay,
+                             /* aIsInterval */ false,
+                             Timeout::Reason::eDelayedWebTaskTimeout, rv);
+  return rv.StealNSResult();
+}
+
+bool WebTaskSchedulerWorker::DispatchEventLoopRunnable() {
+  RefPtr<WebTaskWorkerRunnable> runnable =
+      new WebTaskWorkerRunnable(mWorkerPrivate, this);
+  return runnable->Dispatch();
+}
+}  // namespace mozilla::dom
diff --git a/dom/webscheduling/WebTaskSchedulerWorker.h b/dom/webscheduling/WebTaskSchedulerWorker.h
new file mode 100644
index 0000000000..4af987736e
--- /dev/null
+++ b/dom/webscheduling/WebTaskSchedulerWorker.h
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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/. */
+
+#ifndef mozilla_dom_WebTaskSchedulerWorker_h
+#define mozilla_dom_WebTaskSchedulerWorker_h
+
+#include "WebTaskScheduler.h"
+
+#include "mozilla/LinkedList.h"
+#include "mozilla/dom/WorkerRunnable.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WebTaskSchedulingBinding.h"
+
+namespace mozilla::dom {
+
+class WebTaskWorkerRunnable : public WorkerSameThreadRunnable {
+ public:
+  WebTaskWorkerRunnable(WorkerPrivate* aWorkerPrivate,
+                        WebTaskSchedulerWorker* aSchedulerWorker);
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override;
+
+ private:
+  ~WebTaskWorkerRunnable() = default;
+  WeakPtr<WebTaskSchedulerWorker> mSchedulerWorker;
+};
+
+class WebTaskSchedulerWorker final : public WebTaskScheduler {
+ public:
+  explicit WebTaskSchedulerWorker(WorkerPrivate* aWorkerPrivate);
+
+ private:
+  ~WebTaskSchedulerWorker() = default;
+
+  nsresult SetTimeoutForDelayedTask(WebTask* aTask, uint64_t aDelay) override;
+  bool DispatchEventLoopRunnable() override;
+
+  CheckedUnsafePtr<WorkerPrivate> mWorkerPrivate;
+};
+}  // namespace mozilla::dom
+#endif
diff --git a/dom/webscheduling/moz.build b/dom/webscheduling/moz.build
new file mode 100644
index 0000000000..b30b87972c
--- /dev/null
+++ b/dom/webscheduling/moz.build
@@ -0,0 +1,27 @@
+# -*- 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: Performance")
+
+EXPORTS.mozilla.dom += [
+    "TaskSignal.h",
+    "WebTaskController.h",
+    "WebTaskScheduler.h",
+    "WebTaskSchedulerMainThread.h",
+    "WebTaskSchedulerWorker.h",
+]
+
+UNIFIED_SOURCES += [
+    "WebTaskController.cpp",
+    "WebTaskScheduler.cpp",
+    "WebTaskSchedulerMainThread.cpp",
+    "WebTaskSchedulerWorker.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"