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

chrome/browser/autocomplete/search_provider_unittest.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 "base/metrics/field_trial.h"
 #include "base/prefs/pref_service.h"
 #include "base/run_loop.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
 #include "chrome/browser/autocomplete/autocomplete_controller.h"
 #include "chrome/browser/autocomplete/autocomplete_input.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_provider.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
 #include "chrome/browser/autocomplete/history_url_provider.h"
@@ skipping 2142 matching lines @@
       } else {
         ASSERT_NE(sug_end, sug_it) << "Failed to find " << suggestion;
         EXPECT_EQ(ASCIIToUTF16(suggestion), sug_it->suggestion());
         ++sug_it;
       }
     }
     EXPECT_EQ(sug_end, sug_it);
     EXPECT_EQ(nav_end, nav_it);
   }
 }