Base: Fix a deadlock during shutdown of SequencedWorkerPool.

base/threading/sequenced_worker_pool.cc

Index: base/threading/sequenced_worker_pool.cc
diff --git a/base/threading/sequenced_worker_pool.cc b/base/threading/sequenced_worker_pool.cc
index 89224f74aa4d7b5cafa4398e5b6d2a3c6121c5bb..19b81b7b4b32a32d58bd74e2f8e237aa082f1722 100644
--- a/base/threading/sequenced_worker_pool.cc
+++ b/base/threading/sequenced_worker_pool.cc
@@ -798,9 +798,11 @@ void SequencedWorkerPool::Inner::ThreadLoop(Worker* this_worker) {
         // to run them. Also, there may be some tasks stuck behind running
         // ones with the same sequence token, but additional threads won't
         // help this case.
-        if (shutdown_called_ &&
-            blocking_shutdown_pending_task_count_ == 0)
+        if (shutdown_called_ && blocking_shutdown_pending_task_count_ == 0) {
+          AutoUnlock unlock(lock_);
+          delete_these_outside_lock.clear();
           break;
+        }
         waiting_thread_count_++;
 
         switch (status) {