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

ui/views/examples/combobox_example.cc

 // 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.
 
 #include "ui/views/examples/combobox_example.h"
 
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/views/controls/combobox/combobox.h"
 #include "ui/views/layout/fill_layout.h"
 
 namespace views {
 namespace examples {
 
 ComboboxModelExample::ComboboxModelExample() {
 }
 
@@ skipping 24 matching lines @@
 }
 
 void ComboboxExample::OnSelectedIndexChanged(Combobox* combobox) {
   DCHECK_EQ(combobox_, combobox);
   PrintStatus("Selected: %s", UTF16ToUTF8(combobox_model_.GetItemAt(
       combobox->selected_index())).c_str());
 }
 
 }  // namespace examples
 }  // namespace views