Use a direct include of strings headers in chrome/auto*/.

chrome/browser/autocomplete/search_provider.cc

 // Copyright 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.
 
 #include "chrome/browser/autocomplete/search_provider.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/auto_reset.h"
 #include "base/callback.h"
 #include "base/i18n/break_iterator.h"
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/icu_string_conversions.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
-#include "base/string16.h"
-#include "base/string_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
 #include "chrome/browser/autocomplete/autocomplete_result.h"
 #include "chrome/browser/autocomplete/keyword_provider.h"
 #include "chrome/browser/autocomplete/url_prefix.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
@@ skipping 1571 matching lines @@
     it->set_relevance(max_query_relevance);
   }
 }
 
 void SearchProvider::UpdateDone() {
   // We're done when the timer isn't running, there are no suggest queries
   // pending, and we're not waiting on Instant.
   done_ = IsNonInstantSearchDone() &&
       (instant_finalized_ || !chrome::IsInstantEnabled(profile_));
 }