Revert of Remove SequencedWorkerPool::PostWorkerTask().

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 d55e21b1a26f097e6ec16cc37359cd3891b32eb4..1215b2a327fffa47c4bfd80b3046ca914afc35e9 100644
--- a/base/threading/sequenced_worker_pool.cc
+++ b/base/threading/sequenced_worker_pool.cc
@@ -1545,6 +1545,13 @@
   return new SequencedWorkerPoolTaskRunner(this, shutdown_behavior);
 }
 
+bool SequencedWorkerPool::PostWorkerTask(
+    const tracked_objects::Location& from_here,
+    OnceClosure task) {
+  return inner_->PostTask(NULL, SequenceToken(), BLOCK_SHUTDOWN, from_here,
+                          std::move(task), TimeDelta());
+}
+
 bool SequencedWorkerPool::PostWorkerTaskWithShutdownBehavior(
     const tracked_objects::Location& from_here,
     OnceClosure task,