Use a direct include of strings headers in ui/, part 3.

ui/views/controls/tree/tree_view_selector.h

 // Copyright (c) 2013 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_VIEWS_CONTROLS_TREE_TREE_VIEW_SELECTOR_H_
 #define UI_VIEWS_CONTROLS_TREE_TREE_VIEW_SELECTOR_H_
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/time.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/views/views_export.h"
 
 namespace views {
 
 class TreeView;
 
 // TreeViewSelector is used to change the selection in the tree as the user
 // types characters.
@@ skipping 48 matching lines @@
   base::TimeTicks time_of_last_key_;
 
   string16 current_text_;
 
   DISALLOW_COPY_AND_ASSIGN(TreeViewSelector);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TREE_TREE_VIEW_SELECTOR_H_