Use a direct include of strings headers in base/.

base/nix/mime_util_xdg.cc

 // 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.
 
 #include "base/nix/mime_util_xdg.h"
 
 #include <cstdlib>
 #include <list>
 #include <map>
 #include <vector>
 
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/nix/xdg_util.h"
-#include "base/string_util.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "base/synchronization/lock.h"
 #include "base/third_party/xdg_mime/xdgmime.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 
 namespace base {
 namespace nix {
 
 namespace {
 
@@ skipping 615 matching lines @@
       icon_file = LookupIconInDefaultTheme(icon_names[i], size);
       if (!icon_file.empty())
         return icon_file;
     }
   }
   return FilePath();
 }
 
 }  // namespace nix
 }  // namespace base