Automated IWYU fix for TaskRunner includes.

content/child/indexed_db/indexed_db_callbacks_impl.h

 // 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.
 
 #ifndef CONTENT_CHILD_INDEXED_DB_INDEXED_DB_CALLBACKS_IMPL_H_
 #define CONTENT_CHILD_INDEXED_DB_INDEXED_DB_CALLBACKS_IMPL_H_
 
+#include "base/single_thread_task_runner.h"
 #include "content/common/indexed_db/indexed_db.mojom.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
 
 namespace blink {
 class WebIDBCallbacks;
 struct WebIDBValue;
 }
 
 namespace content {
 
@@ skipping 96 matching lines @@
   // executes tasks and must be destroyed there.
   InternalState* internal_state_;
   scoped_refptr<base::SingleThreadTaskRunner> callback_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(IndexedDBCallbacksImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_INDEXED_DB_INDEXED_DB_CALLBACKS_IMPL_H_