SequenceManager: Remove IsCancelled crash keys

They didn't reveal any leads, and are somewhat expensive.

Bug: 798554, 897751
Change-Id: Id22b59ccd43b823902c48a4b5f324ccea07e9649
Reviewed-on: https://chromium-review.googlesource.com/c/1301463Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603082}

base/task/sequence_manager/sequence_manager_impl.cc

@@ -723,17 +723,6 @@ WeakPtr<SequenceManagerImpl> SequenceManagerImpl::GetWeakPtr() {
   return weak_factory_.GetWeakPtr();
 }
 
-bool SequenceManagerImpl::SetCrashKeysAndCheckIsTaskCancelled(
-    const PendingTask& task) const {
-#if !defined(OS_NACL)
-  debug::SetCrashKeyString(main_thread_only().file_name_crash_key,
-                           task.posted_from.file_name());
-  debug::SetCrashKeyString(main_thread_only().function_name_crash_key,
-                           task.posted_from.function_name());
-#endif  // OS_NACL
-  return task.task.IsCancelled();
-}
-
 void SequenceManagerImpl::SetDefaultTaskRunner(
     scoped_refptr<SingleThreadTaskRunner> task_runner) {
   controller_->SetDefaultTaskRunner(task_runner);

base/task/sequence_manager/sequence_manager_impl.h

@@ -160,9 +160,6 @@ class BASE_EXPORT SequenceManagerImpl
 
   WeakPtr<SequenceManagerImpl> GetWeakPtr();
 
-  // TODO(alexclarke): Remove when possible.
-  bool SetCrashKeysAndCheckIsTaskCancelled(const PendingTask& task) const;
-
  protected:
   // Create a task queue manager where |controller| controls the thread
   // on which the tasks are eventually run.

base/task/sequence_manager/task_queue_impl.cc

@@ -417,15 +417,10 @@ Optional<TimeTicks> TaskQueueImpl::GetNextScheduledWakeUp() {
 void TaskQueueImpl::WakeUpForDelayedWork(LazyNow* lazy_now) {
   // Enqueue all delayed tasks that should be running now, skipping any that
   // have been canceled.
-  const SequenceManagerImpl* sequence_manager =
-      main_thread_only().sequence_manager;
   while (!main_thread_only().delayed_incoming_queue.empty()) {
     Task& task =
         const_cast<Task&>(main_thread_only().delayed_incoming_queue.top());
-    // TODO(alexclarke): Use IsCancelled once we've understood the bug.
-    // See http://crbug.com/798554
-    if (!task.task ||
-        sequence_manager->SetCrashKeysAndCheckIsTaskCancelled(task)) {
+    if (!task.task || task.task.IsCancelled()) {
       main_thread_only().delayed_incoming_queue.pop();
       continue;
     }
@@ -1040,9 +1035,7 @@ void TaskQueueImpl::DelayedIncomingQueue::SweepCancelledTasks(
     const SequenceManagerImpl* sequence_manager) {
   std::priority_queue<Task> remaining_tasks;
   while (!empty()) {
-    // TODO(alexclarke): Use IsCancelled once we've understood the bug.
-    // See http://crbug.com/798554
-    if (!sequence_manager->SetCrashKeysAndCheckIsTaskCancelled(top())) {
+    if (!top().task.IsCancelled()) {
       if (top().is_high_res)
         pending_high_res_tasks_++;
       remaining_tasks.push(std::move(const_cast<Task&>(top())));

base/task/sequence_manager/work_queue.cc

@@ -156,13 +156,8 @@ Task WorkQueue::TakeTaskFromWorkQueue() {
 bool WorkQueue::RemoveAllCanceledTasksFromFront() {
   DCHECK(work_queue_sets_);
   bool task_removed = false;
-  const SequenceManagerImpl* sequence_manager = task_queue_->sequence_manager();
-  // TODO(alexclarke): Use IsCancelled once we've understood the bug.
-  // See http://crbug.com/798554
-  while (
-      !tasks_.empty() &&
-      (!tasks_.front().task ||
-       sequence_manager->SetCrashKeysAndCheckIsTaskCancelled(tasks_.front()))) {
+  while (!tasks_.empty() &&
+         (!tasks_.front().task || tasks_.front().task.IsCancelled())) {
     tasks_.pop_front();
     task_removed = true;
   }