Revert of [heap] Cancel tasks before tearing down the heap. (patchset #2...

Revert of [heap] Cancel tasks before tearing down the heap. (patchset #2 id:20001 of https://codereview.chromium.org/2413203004/ )

Reason for revert:
Timeout on gc stress bot.

Original issue's description:
> [heap] Cancel tasks before tearing down the heap.
>
> BUG=chromium:654343
>
> Committed: https://crrev.com/9365463d6f1fc11b2369fff63ca0ac825c61eae4
> Cr-Commit-Position: refs/heads/master@{#40272}

TBR=mlippautz@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:654343

Review-Url: https://codereview.chromium.org/2414073002
Cr-Commit-Position: refs/heads/master@{#40279}

src/cancelable-task.cc

@@ -26,20 +26,14 @@ Cancelable::~Cancelable() {
   }
 }
 
-CancelableTaskManager::CancelableTaskManager()
-    : task_id_counter_(0), canceled_(false) {}
+CancelableTaskManager::CancelableTaskManager() : task_id_counter_(0) {}
 
 uint32_t CancelableTaskManager::Register(Cancelable* task) {
   base::LockGuard<base::Mutex> guard(&mutex_);
   uint32_t id = ++task_id_counter_;
   // The loop below is just used when task_id_counter_ overflows.
   while (cancelable_tasks_.count(id) > 0) ++id;
-  if (canceled_) {
-    bool successfully_canceled_task = task->Cancel();
-    CHECK(successfully_canceled_task);
-  } else {
-    cancelable_tasks_[id] = task;
-  }
+  cancelable_tasks_[id] = task;
   return id;
 }
 
@@ -75,7 +69,6 @@ void CancelableTaskManager::CancelAndWait() {
   // of canceling we wait for the background tasks that have already been
   // started.
   base::LockGuard<base::Mutex> guard(&mutex_);
-  canceled_ = true;
 
   // Cancelable tasks could be running or could potentially register new
   // tasks, requiring a loop here.

src/cancelable-task.h

@@ -40,8 +40,7 @@ class CancelableTaskManager {
   bool TryAbort(uint32_t id);
 
   // Cancels all remaining registered tasks and waits for tasks that are
-  // already running. After this function is called all subsequent new tasks
-  // will be cancelled on creation.
+  // already running.
   void CancelAndWait();
 
  private:
@@ -60,8 +59,6 @@ class CancelableTaskManager {
   base::ConditionVariable cancelable_tasks_barrier_;
   base::Mutex mutex_;
 
-  bool canceled_;
-
   friend class Cancelable;
 
   DISALLOW_COPY_AND_ASSIGN(CancelableTaskManager);

src/isolate.cc

@@ -2182,8 +2182,6 @@ void Isolate::ClearSerializerData() {
 void Isolate::Deinit() {
   TRACE_ISOLATE(deinit);
 
-  cancelable_task_manager()->CancelAndWait();
-
   debug()->Unload();
 
   FreeThreadResources();
@@ -2234,6 +2232,8 @@ void Isolate::Deinit() {
   delete interpreter_;
   interpreter_ = NULL;
 
+  cancelable_task_manager()->CancelAndWait();
+
   delete cpu_profiler_;
   cpu_profiler_ = NULL;