Automated IWYU fix for TaskRunner includes.

content/child/indexed_db/webidbdatabase_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_INDEXED_DB_WEBIDBDATABASE_IMPL_H_
 #define CONTENT_CHILD_INDEXED_DB_WEBIDBDATABASE_IMPL_H_
 
 #include <stdint.h>
 
 #include <set>
 
 #include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
 #include "content/common/content_export.h"
 #include "content/common/indexed_db/indexed_db.mojom.h"
 #include "content/common/indexed_db/indexed_db_constants.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBCursor.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBDatabase.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBTypes.h"
 
 namespace blink {
 class WebBlobInfo;
 class WebIDBCallbacks;
@@ skipping 119 matching lines @@
   size_t max_put_value_size_ = kMaxIDBMessageSizeInBytes;
 
   IOThreadHelper* helper_;
   std::set<int32_t> observer_ids_;
   scoped_refptr<base::SingleThreadTaskRunner> io_runner_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_INDEXED_DB_WEBIDBDATABASE_IMPL_H_