Backed out 8 changesets (bug 1920115) for causing multiple failures.

Backed out changeset 2d0905a92f2c (bug 1920115)
Backed out changeset 67bf260fe59b (bug 1920115)
Backed out changeset 4739af17e757 (bug 1920115)
Backed out changeset 0773f669c498 (bug 1920115)
Backed out changeset 4b579a1c9b46 (bug 1920115)
Backed out changeset 79b3b0148eb4 (bug 1920115)
Backed out changeset 78181c32bdc6 (bug 1920115)
Backed out changeset 912cf1adac80 (bug 1920115)

dom/base/IdleRequest.cpp

@@ -13,7 +13,6 @@
 #include "mozilla/dom/WindowBinding.h"
 #include "nsComponentManagerUtils.h"
 #include "nsPIDOMWindow.h"
-#include "mozilla/dom/WebTaskScheduler.h"
 
 namespace mozilla::dom {
 
@@ -55,20 +54,7 @@ void IdleRequest::IdleRun(nsPIDOMWindowInner* aWindow,
       new IdleDeadline(aWindow, aDidTimeout, aDeadline);
   RefPtr<IdleRequestCallback> callback(std::move(mCallback));
   MOZ_ASSERT(!mCallback);
-
-  RefPtr<nsGlobalWindowInner> innerWindow = nsGlobalWindowInner::Cast(aWindow);
-  // https://wicg.github.io/scheduling-apis/#sec-patches-invoke-idle-callbacks
-  // Let state be a new scheduling state.
-  RefPtr<WebTaskSchedulingState> newState = new WebTaskSchedulingState();
-  // Set state’s priority source to the result of creating a fixed priority
-  // unabortable task signal given "background" and realm.
-  newState->SetPrioritySource(
-      new TaskSignal(aWindow->AsGlobal(), TaskPriority::Background));
-  // Set event loop’s current scheduling state to state.
-  innerWindow->SetWebTaskSchedulingState(newState);
   callback->Call(*deadline, "requestIdleCallback handler");
-  // Set event loop’s current scheduling state to null.
-  innerWindow->SetWebTaskSchedulingState(nullptr);
 }
 
 }  // namespace mozilla::dom

dom/base/TimeoutManager.cpp

@@ -25,7 +25,6 @@
 #include "mozilla/net/WebSocketEventService.h"
 #include "mozilla/MediaManager.h"
 #include "mozilla/dom/WorkerScope.h"
-#include "mozilla/dom/WebTaskScheduler.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -663,17 +662,6 @@ void TimeoutManager::RunTimeout(const TimeStamp& aNow,
     return;
   }
 
-  if (!GetInnerWindow()) {
-    // Workers don't use TaskController at the moment, so all the
-    // runnables have the same priorities. So we special case it
-    // here to allow "higher" prority tasks to run first before
-    // timers.
-    if (mGlobalObject.HasScheduledNormalOrHighPriorityWebTasks()) {
-      MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(aNow));
-      return;
-    }
-  }
-
   Timeouts& timeouts(aProcessIdle ? mIdleTimeouts : mTimeouts);
 
   // Limit the overall time spent in RunTimeout() to reduce jank.
@@ -975,12 +963,8 @@ void TimeoutManager::RunTimeout(const TimeStamp& aNow,
       }
       // Check to see if we have run out of time to execute timeout handlers.
       // If we've exceeded our time budget then terminate the loop immediately.
-      //
-      // Or if there are high priority tasks dispatched by the Scheduler API,
-      // they should run first before timers.
       TimeDuration elapsed = now - start;
-      if (elapsed >= totalTimeLimit ||
-          mGlobalObject.HasScheduledNormalOrHighPriorityWebTasks()) {
+      if (elapsed >= totalTimeLimit) {
         // We ran out of time.  Make sure to schedule the executor to
         // run immediately for the next timer, if it exists.  Its possible,
         // however, that the last timeout handler suspended the window.  If

dom/base/nsGlobalWindowInner.cpp

@@ -1400,8 +1400,6 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(nsGlobalWindowInner)
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWebTaskScheduler)
 
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWebTaskSchedulingState)
-
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTrustedTypePolicyFactory)
 
 #ifdef MOZ_WEBSPEECH
@@ -1513,8 +1511,6 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGlobalWindowInner)
     NS_IMPL_CYCLE_COLLECTION_UNLINK(mWebTaskScheduler)
   }
 
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mWebTaskSchedulingState)
-
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mTrustedTypePolicyFactory)
 
 #ifdef MOZ_WEBSPEECH
@@ -1831,7 +1827,6 @@ void nsGlobalWindowInner::InitDocumentDependentState(JSContext* aCx) {
   if (mWebTaskScheduler) {
     mWebTaskScheduler->Disconnect();
     mWebTaskScheduler = nullptr;
-    mWebTaskSchedulingState = nullptr;
   }
 
   // This must be called after nullifying the internal objects because here we
@@ -2900,10 +2895,6 @@ bool nsPIDOMWindowInner::IsCurrentInnerWindow() const {
   return outer && outer->GetCurrentInnerWindow() == this;
 }
 
-bool nsGlobalWindowInner::HasScheduledNormalOrHighPriorityWebTasks() const {
-  return gNumNormalOrHighPriorityQueuesHaveTaskScheduledMainThread > 0;
-}
-
 bool nsPIDOMWindowInner::IsFullyActive() const {
   WindowContext* wc = GetWindowContext();
   if (!wc || wc->IsDiscarded() || !wc->IsCurrent()) {
@@ -4104,11 +4095,6 @@ WebTaskScheduler* nsGlobalWindowInner::Scheduler() {
   return mWebTaskScheduler;
 }
 
-inline void nsGlobalWindowInner::SetWebTaskSchedulingState(
-    WebTaskSchedulingState* aState) {
-  mWebTaskSchedulingState = aState;
-}
-
 bool nsGlobalWindowInner::Find(const nsAString& aString, bool aCaseSensitive,
                                bool aBackwards, bool aWrapAround,
                                bool aWholeWord, bool aSearchInFrames,

dom/base/nsGlobalWindowInner.h

@@ -130,7 +130,6 @@ class Selection;
 struct SizeToContentConstraints;
 class WebTaskScheduler;
 class WebTaskSchedulerMainThread;
-class WebTaskSchedulingState;
 class SpeechSynthesis;
 class Timeout;
 class TrustedTypePolicyFactory;
@@ -338,7 +337,6 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   virtual bool HasActiveIndexedDBDatabases() override;
   virtual bool HasActivePeerConnections() override;
   virtual bool HasOpenWebSockets() const override;
-  virtual bool HasScheduledNormalOrHighPriorityWebTasks() const override;
   void SyncStateFromParentWindow();
 
   // Called on the current inner window of a browsing context when its
@@ -963,12 +961,6 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   bool CrossOriginIsolated() const override;
 
   mozilla::dom::WebTaskScheduler* Scheduler();
-  void SetWebTaskSchedulingState(
-      mozilla::dom::WebTaskSchedulingState* aState) override;
-  mozilla::dom::WebTaskSchedulingState* GetWebTaskSchedulingState()
-      const override {
-    return mWebTaskSchedulingState;
-  }
 
  protected:
   // Web IDL helpers
@@ -1285,7 +1277,6 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   RefPtr<mozilla::dom::ContentMediaController> mContentMediaController;
 
   RefPtr<mozilla::dom::WebTaskSchedulerMainThread> mWebTaskScheduler;
-  RefPtr<mozilla::dom::WebTaskSchedulingState> mWebTaskSchedulingState;
 
   RefPtr<mozilla::dom::TrustedTypePolicyFactory> mTrustedTypePolicyFactory;
 

dom/base/nsIGlobalObject.h

@@ -53,7 +53,6 @@ class ServiceWorkerContainer;
 class ServiceWorkerRegistration;
 class ServiceWorkerRegistrationDescriptor;
 class StorageManager;
-class WebTaskSchedulingState;
 enum class CallerType : uint32_t;
 }  // namespace dom
 namespace ipc {
@@ -195,13 +194,6 @@ class nsIGlobalObject : public nsISupports {
     return nullptr;
   }
 
-  virtual void SetWebTaskSchedulingState(
-      mozilla::dom::WebTaskSchedulingState* aState) {}
-  virtual mozilla::dom::WebTaskSchedulingState* GetWebTaskSchedulingState()
-      const {
-    return nullptr;
-  }
-
   // For globals with a concept of a Base URI (windows, workers), the base URI,
   // nullptr otherwise.
   virtual nsIURI* GetBaseURI() const;
@@ -345,10 +337,6 @@ class nsIGlobalObject : public nsISupports {
 
   virtual bool IsXPCSandbox() { return false; }
 
-  virtual bool HasScheduledNormalOrHighPriorityWebTasks() const {
-    return false;
-  }
-
   /**
    * Report a localized error message to the error console.  Currently this
    * amounts to a wrapper around nsContentUtils::ReportToConsole for window

dom/script/ScriptSettings.cpp

@@ -233,13 +233,6 @@ nsIGlobalObject* GetCurrentGlobal() {
   return xpc::NativeGlobal(global);
 }
 
-WebTaskSchedulingState* GetWebTaskSchedulingState() {
-  if (const nsIGlobalObject* global = GetEntryGlobal()) {
-    return global->GetWebTaskSchedulingState();
-  }
-  return nullptr;
-}
-
 nsIPrincipal* GetWebIDLCallerPrincipal() {
   MOZ_ASSERT(NS_IsMainThread());
   ScriptSettingsStackEntry* entry = ScriptSettingsStack::EntryPoint();

dom/script/ScriptSettings.h

@@ -35,7 +35,6 @@ namespace mozilla {
 namespace dom {
 
 class Document;
-class WebTaskSchedulingState;
 
 /*
  * Per thread setup/teardown routines. Init and Destroy should be invoked
@@ -96,8 +95,6 @@ nsIGlobalObject* GetIncumbentGlobal();
 // Returns the global associated with the current compartment. This may be null.
 nsIGlobalObject* GetCurrentGlobal();
 
-WebTaskSchedulingState* GetWebTaskSchedulingState();
-
 // JS-implemented WebIDL presents an interesting situation with respect to the
 // subject principal. A regular C++-implemented API can simply examine the
 // compartment of the most-recently-executed script, and use that to infer the

dom/webidl/WebTaskScheduling.webidl

@@ -31,9 +31,6 @@ interface Scheduler {
     SchedulerPostTaskCallback callback,
     optional SchedulerPostTaskOptions options = {}
   );
-
-  [BinaryName="yieldImpl"]
-  Promise<undefined> yield();
 };
 
 dictionary TaskControllerInit {

dom/webscheduling/TaskSignal.h

@@ -11,6 +11,7 @@
 #include "mozilla/DOMEventTargetHelper.h"
 #include "mozilla/dom/AbortSignal.h"
 #include "mozilla/dom/WebTaskSchedulingBinding.h"
+#include "WebTaskScheduler.h"
 
 namespace mozilla::dom {
 class TaskSignal : public AbortSignal {
@@ -39,9 +40,15 @@ class TaskSignal : public AbortSignal {
     mPriorityChanging = aPriorityChanging;
   }
 
-  void RunPriorityChangeAlgorithms();
+  void SetWebTaskScheduler(WebTaskScheduler* aScheduler) {
+    mSchedulers.AppendElement(aScheduler);
+  }
 
-  void SetWebTaskScheduler(WebTaskScheduler* aScheduler);
+  void RunPriorityChangeAlgorithms() {
+    for (const WeakPtr<WebTaskScheduler>& scheduler : mSchedulers) {
+      scheduler->RunTaskSignalPriorityChange(this);
+    }
+  }
 
  private:
   TaskPriority mPriority;