Bug 1874080 - Nullify WebTaskSchedulerWorker::mWorkerPrivate while Disconnect(). r=smaug, a=RyanVM

Differential Revision: https://phabricator.services.mozilla.com/D198569

dom/webscheduling/WebTaskScheduler.h

@@ -113,7 +113,7 @@ class WebTaskScheduler : public nsWrapperCache, public SupportsWeakPtr {
 
   WebTask* GetNextTask() const;
 
-  void Disconnect();
+  virtual void Disconnect();
 
   void RunTaskSignalPriorityChange(TaskSignal* aTaskSignal);
 

dom/webscheduling/WebTaskSchedulerWorker.cpp

@@ -36,6 +36,9 @@ bool WebTaskWorkerRunnable::WorkerRun(JSContext* aCx,
 
 nsresult WebTaskSchedulerWorker::SetTimeoutForDelayedTask(WebTask* aTask,
                                                           uint64_t aDelay) {
+  if (!mWorkerPrivate) {
+    return NS_ERROR_UNEXPECTED;
+  }
   JSContext* cx = nsContentUtils::GetCurrentJSContext();
   if (!cx) {
     return NS_ERROR_UNEXPECTED;
@@ -52,8 +55,18 @@ nsresult WebTaskSchedulerWorker::SetTimeoutForDelayedTask(WebTask* aTask,
 }
 
 bool WebTaskSchedulerWorker::DispatchEventLoopRunnable() {
+  if (!mWorkerPrivate) {
+    return false;
+  }
   RefPtr<WebTaskWorkerRunnable> runnable =
       new WebTaskWorkerRunnable(mWorkerPrivate, this);
   return runnable->Dispatch();
 }
+
+void WebTaskSchedulerWorker::Disconnect() {
+  if (mWorkerPrivate) {
+    mWorkerPrivate = nullptr;
+  }
+  WebTaskScheduler::Disconnect();
+}
 }  // namespace mozilla::dom

dom/webscheduling/WebTaskSchedulerWorker.h

@@ -34,6 +34,8 @@ class WebTaskSchedulerWorker final : public WebTaskScheduler {
  public:
   explicit WebTaskSchedulerWorker(WorkerPrivate* aWorkerPrivate);
 
+  void Disconnect() override;
+
  private:
   ~WebTaskSchedulerWorker() = default;