Remove unused include in sequenced_worker_pool.h

remoting/client/queued_task_poster_unittest.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 "remoting/client/queued_task_poster.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/single_thread_task_runner.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace remoting {
 
 class QueuedTaskPosterTest : public testing::Test {
  public:
   QueuedTaskPosterTest();
   void SetUp() override;
@@ skipping 113 matching lines @@
 
   poster_->AddTask(AssertExecutionOrderClosure(4));
   poster_->AddTask(AssertExecutionOrderClosure(5));
   poster_->AddTask(AssertExecutionOrderClosure(6));
 
   RunUntilPosterDone();
   EXPECT_EQ(6, current_execution_order_);
 }
 
 }  // namespace remoting