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

ui/views/controls/textfield/native_textfield_views_unittest.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 <set>
 #include <string>
 #include <vector>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/pickle.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "googleurl/src/gurl.h"
 #include "grit/ui_strings.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/events/event.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/keycodes/keyboard_codes.h"
@@ skipping 1894 matching lines @@
   textfield_view_->OnGestureEvent(&tap_down);
   // Create a new long press event since the previous one is not marked handled.
   GestureEventForTest long_press2(ui::ET_GESTURE_LONG_PRESS, eventX, eventY, 0);
   textfield_view_->OnGestureEvent(&long_press2);
   EXPECT_STR_EQ("hello", textfield_->GetSelectedText());
   EXPECT_FALSE(GetTouchSelectionController());
 }
 #endif
 
 }  // namespace views