Use a direct include of strings headers in ui/, part 1.

ui/base/l10n/l10n_util_mac.h

 // Copyright (c) 2011 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 UI_BASE_L10N_L10N_UTIL_MAC_H_
 #define UI_BASE_L10N_L10N_UTIL_MAC_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/base/ui_export.h"
 
 #ifdef __OBJC__
 @class NSString;
 #else
 class NSString;
 #endif
 
 namespace l10n_util {
 
@@ skipping 50 matching lines @@
                                           const string16& c,
                                           const string16& d);
 
 // Support the override of the locale with the value from Cocoa.
 UI_EXPORT void OverrideLocaleWithCocoaLocale();
 UI_EXPORT const std::string& GetLocaleOverride();
 
 }  // namespace l10n_util
 
 #endif  // UI_BASE_L10N_L10N_UTIL_MAC_H_