TaskScheduler: Set the IO allowed bit in TaskTracker::RunTask().

base/task_scheduler/task_tracker.cc

Index: base/task_scheduler/task_tracker.cc
diff --git a/base/task_scheduler/task_tracker.cc b/base/task_scheduler/task_tracker.cc
index d06a84dc1f47dd7a4cb16f4463a4fa0c486a6dca..49a33be8c24b113f82c0ab0a1ad1047465aee2bb 100644
--- a/base/task_scheduler/task_tracker.cc
+++ b/base/task_scheduler/task_tracker.cc
@@ -219,12 +219,12 @@ bool TaskTracker::RunTask(std::unique_ptr<Task> task,
   const bool is_delayed = !task->delayed_run_time.is_null();
 
   if (can_run_task) {
-    // All tasks run through here and the scheduler itself doesn't use
-    // singletons. Therefore, it isn't necessary to reset the singleton allowed
-    // bit after running the task.
-    ThreadRestrictions::SetSingletonAllowed(
-        task->traits.shutdown_behavior() !=
-        TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN);
+    const bool previous_singleton_allowed =
+        ThreadRestrictions::SetSingletonAllowed(
+            task->traits.shutdown_behavior() !=
+            TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN);
+    const bool previous_io_allowed =
+        ThreadRestrictions::SetIOAllowed(task->traits.with_file_io());
 
     {
       // Set up SequenceToken as expected for the scope of the task.
@@ -261,6 +261,9 @@ bool TaskTracker::RunTask(std::unique_ptr<Task> task,
       PerformRunTask(std::move(task));
     }
 
+    ThreadRestrictions::SetSingletonAllowed(previous_singleton_allowed);

[robliao, 2016/11/28 22:17:41]

I presume this will change with the other CL that touches this?

[fdoray, 2016/11/28 22:36:15]

Done. Reordered in this CL.

+    ThreadRestrictions::SetIOAllowed(previous_io_allowed);
+
     AfterRunTask(shutdown_behavior);
   }