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

chrome/browser/autocomplete/autocomplete_input.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 CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "googleurl/src/gurl.h"
 #include "googleurl/src/url_parse.h"
 
 // The user input for an autocomplete query.  Allows copying.
 class AutocompleteInput {
  public:
   // Note that the type below may be misleading.  For example, "http:/" alone
   // cannot be opened as a URL, so it is marked as a QUERY; yet the user
   // probably intends to type more and have it eventually become a URL, so we
   // need to make sure we still run it through inline autocomplete.
@@ skipping 166 matching lines @@
   url_parse::Parsed parts_;
   string16 scheme_;
   GURL canonicalized_url_;
   bool prevent_inline_autocomplete_;
   bool prefer_keyword_;
   bool allow_exact_keyword_match_;
   MatchesRequested matches_requested_;
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_