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

ui/aura/window.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 UI_AURA_WINDOW_H_
 #define UI_AURA_WINDOW_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/client/window_types.h"
 #include "ui/aura/window_observer.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/base/events/event_target.h"
 #include "ui/base/gestures/gesture_types.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/layer_delegate.h"
 #include "ui/compositor/layer_owner.h"
 #include "ui/compositor/layer_type.h"
@@ skipping 489 matching lines @@
   };
 
   std::map<const void*, Value> prop_map_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_