Use a direct include of utf_string_conversions.h in android_webview/, apps/, ash/, base/.

ash/system/web_notification/web_notification_tray_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 "ash/system/web_notification/web_notification_tray.h"
 
 #include <vector>
 
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "ash/test/ash_test_base.h"
 #include "base/stringprintf.h"
-#include "base/utf_string_conversions.h"
+#include "base/strings/utf_string_conversions.h"
 #include "ui/message_center/message_center_style.h"
 #include "ui/message_center/message_center_tray.h"
 #include "ui/message_center/message_center_util.h"
 #include "ui/message_center/notification_list.h"
 #include "ui/message_center/notification_types.h"
 #include "ui/message_center/views/message_center_bubble.h"
 #include "ui/message_center/views/message_popup_bubble.h"
 #include "ui/message_center/views/message_popup_collection.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/layout/fill_layout.h"
@@ skipping 167 matching lines @@
     NotificationList::PopupNotifications popups =
         GetMessageCenter()->GetPopupNotifications();
     EXPECT_EQ(message_center::kMaxVisiblePopupNotifications, popups.size());
   } else {
     EXPECT_EQ(message_center::kMaxVisiblePopupNotifications,
               GetTray()->GetPopupBubbleForTest()->NumMessageViewsForTest());
   }
 }
 
 }  // namespace ash