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

ui/aura/remote_root_window_host_win.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_REMOTE_ROOT_WINDOW_HOST_WIN_H_
 #define UI_AURA_REMOTE_ROOT_WINDOW_HOST_WIN_H_
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/aura/root_window_host.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace ui {
 class ViewProp;
@@ skipping 175 matching lines @@
   // Set to true if we need to ignore mouse messages until the SetCursorPos
   // operation is acked by the viewer.
   bool ignore_mouse_moves_until_set_cursor_ack_;
 
   DISALLOW_COPY_AND_ASSIGN(RemoteRootWindowHostWin);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_REMOTE_ROOT_WINDOW_HOST_WIN_H_