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

ui/views/controls/textfield/native_textfield_views.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_TEXTFIELD_NATIVE_TEXTFIELD_VIEWS_H_
 #define UI_VIEWS_CONTROLS_TEXTFIELD_NATIVE_TEXTFIELD_VIEWS_H_
 
 #include "base/memory/weak_ptr.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/timer.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/base/touch/touch_editing_controller.h"
 #include "ui/gfx/font.h"
 #include "ui/views/border.h"
 #include "ui/views/context_menu_controller.h"
 #include "ui/views/controls/textfield/native_textfield_wrapper.h"
 #include "ui/views/controls/textfield/textfield_views_model.h"
@@ skipping 317 matching lines @@
   // obscured text. When the timer is running, the last typed char is shown
   // and when the time expires, the last typed char is obscured.
   base::OneShotTimer<NativeTextfieldViews> obscured_reveal_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeTextfieldViews);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TEXTFIELD_NATIVE_TEXTFIELD_VIEWS_H_