Exempt the Service Thread from BLOCK_SHUTDOWN DCHECKs

base/task_scheduler/task_tracker_posix.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/task_scheduler/task_tracker_posix.h"
 
 #include <utility>
 
 #include "base/files/file_descriptor_watcher_posix.h"
-#include "base/logging.h"
 
 namespace base {
 namespace internal {
 
 TaskTrackerPosix::TaskTrackerPosix() = default;
 TaskTrackerPosix::~TaskTrackerPosix() = default;
 
 void TaskTrackerPosix::PerformRunTask(std::unique_ptr<Task> task) {
   DCHECK(watch_file_descriptor_message_loop_);
   FileDescriptorWatcher file_descriptor_watcher(
       watch_file_descriptor_message_loop_);
   TaskTracker::PerformRunTask(std::move(task));
 }
 
+#if DCHECK_IS_ON()
+bool TaskTrackerPosix::IsExemptFromBlockingShutdownChecks() {
+  return service_thread_handle_.is_equal(PlatformThread::CurrentHandle());
+}
+#endif
+
 }  // namespace internal
 }  // namespace base