Remove wstring from autocomplete.

chrome/browser/autocomplete/history_provider_util.cc

 // Copyright (c) 2010 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/autocomplete/history_provider_util.h"
 
 namespace history {
 
 const int kLowQualityMatchTypedLimit = 1;
 const int kLowQualityMatchVisitLimit = 3;
 const int kLowQualityMatchAgeLimitInDays = 3;
 
 HistoryMatch::HistoryMatch()
     : url_info(),
-      input_location(std::wstring::npos),
+      input_location(string16::npos),
       match_in_scheme(false),
       innermost_match(true) {
 }
 
 HistoryMatch::HistoryMatch(const URLRow& url_info,
                            size_t input_location,
                            bool match_in_scheme,
                            bool innermost_match)
     : url_info(url_info),
       input_location(input_location),
       match_in_scheme(match_in_scheme),
       innermost_match(innermost_match) {
 }
 
 bool HistoryMatch::operator==(const GURL& url) const {
   return url_info.url() == url;
 }
 
 base::Time AutocompleteAgeThreshold() {
   return (base::Time::Now() -
           base::TimeDelta::FromDays(kLowQualityMatchAgeLimitInDays));
 }
 
 }