Use utf_string_conversions header in more places.

chrome/browser/history/download_database.cc

 // Copyright (c) 2009 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 "chrome/browser/history/download_database.h"
 
 #include <limits>
 #include <vector>
 
 #include "app/sql/connection.h"
 #include "app/sql/statement.h"
-#include "base/string_util.h"
+#include "base/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/history/download_types.h"
 
 // Download schema:
 //
 //   id             SQLite-generated primary key.
 //   full_path      Location of the download on disk.
 //   url            URL of the downloaded file.
 //   start_time     When the download was started.
@@ skipping 175 matching lines @@
   text.append(WideToUTF8(search_text));
   text.push_back('%');
   statement.BindString(0, text);
   statement.BindString(1, text);
 
   while (statement.Step())
     results->push_back(statement.ColumnInt64(0));
 }
 
 }  // namespace history