Use a direct include of strings headers in base/.

base/values.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.
 
 // This file specifies a recursive data storage class called Value intended for
 // storing setting and other persistable data.  It includes the ability to
 // specify (recursive) lists and dictionaries, so it's fairly expressive.
 // However, the API is optimized for the common case, namely storing a
 // hierarchical tree of simple values.  Given a DictionaryValue root, you can
 // easily do things like:
@@ skipping 12 matching lines @@
 
 #include <iterator>
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 
 // This file declares "using base::Value", etc. at the bottom, so that
 // current code can use these classes without the base namespace. In
 // new code, please always use base::Value, etc. or add your own
 // "using" declaration.
 // http://crbug.com/88666
 namespace base {
 
 class BinaryValue;
 class DictionaryValue;
@@ skipping 476 matching lines @@
 
 }  // namespace base
 
 // http://crbug.com/88666
 using base::DictionaryValue;
 using base::ListValue;
 using base::StringValue;
 using base::Value;
 
 #endif  // BASE_VALUES_H_