IndexedDB: Fix trivial cpplint.py errors

content/common/indexed_db/indexed_db_param_traits.h

 // Copyright (c) 2012 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_COMMON_INDEXED_DB_INDEXED_DB_PARAM_TRAITS_H_
 #define CONTENT_COMMON_INDEXED_DB_INDEXED_DB_PARAM_TRAITS_H_
 
+#include <string>
+
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_param_traits.h"
 
 namespace content {
 class IndexedDBKey;
 class IndexedDBKeyPath;
 class IndexedDBKeyRange;
 }
 
 namespace IPC {
@@ skipping 15 matching lines @@
 };
 
 template <>
 struct ParamTraits<content::IndexedDBKeyPath> {
   typedef content::IndexedDBKeyPath param_type;
   static void Write(Message* m, const param_type& p);
   static bool Read(const Message* m, PickleIterator* iter, param_type* r);
   static void Log(const param_type& p, std::string* l);
 };
 
-} // namespace IPC
+}  // namespace IPC
 
 #endif  // CONTENT_COMMON_INDEXED_DB_INDEXED_DB_PARAM_TRAITS_H_