Add missing #include around sequenced_worker_pool.h in //content, //storage

content/child/fileapi/webfilewriter_impl.h

 // Copyright 2013 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.
 
 #ifndef CONTENT_CHILD_FILEAPI_WEBFILEWRITER_IMPL_H_
 #define CONTENT_CHILD_FILEAPI_WEBFILEWRITER_IMPL_H_
 
 #include <stdint.h>
 
 #include <string>
 
+#include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "content/child/fileapi/webfilewriter_base.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace content {
 
@@ skipping 26 matching lines @@
 
   void RunOnMainThread(const base::Closure& closure);
 
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
   scoped_refptr<WriterBridge> bridge_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_FILEAPI_WEBFILEWRITER_IMPL_H_