[Task Manager] Properly clear worker tasks on profile shutdown.

Fixes PerProfileWorkerTaskTracker so that the WorkerTaskTracker is
notified when there are outstanding tasks that are about to be
deleted.

Bug: 1060506
Change-Id: Ic81ad1557c1e27a8fc96fc079f7447efcc2ce7f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2110350
Auto-Submit: Patrick Monette <pmonette@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751915}

chrome/browser/task_manager/providers/per_profile_worker_task_tracker.cc

@@ -47,7 +47,16 @@ PerProfileWorkerTaskTracker::PerProfileWorkerTaskTracker(
   }
 }
 
-PerProfileWorkerTaskTracker::~PerProfileWorkerTaskTracker() = default;
+PerProfileWorkerTaskTracker::~PerProfileWorkerTaskTracker() {
+  // Notify the |worker_task_provider_| for all outstanding tasks that are about
+  // to be deleted.
+  for (const auto& kv : dedicated_worker_tasks_)
+    worker_task_provider_->OnWorkerTaskRemoved(kv.second.get());
+  for (const auto& kv : shared_worker_tasks_)
+    worker_task_provider_->OnWorkerTaskRemoved(kv.second.get());
+  for (const auto& kv : service_worker_tasks_)
+    worker_task_provider_->OnWorkerTaskRemoved(kv.second.get());
+}
 
 void PerProfileWorkerTaskTracker::OnWorkerStarted(
     content::DedicatedWorkerId dedicated_worker_id,