Convert //ash from scoped_ptr to std::unique_ptr

ash/system/user/user_view.h

Index: ash/system/user/user_view.h
diff --git a/ash/system/user/user_view.h b/ash/system/user/user_view.h
index b258d03495fae1960dadf6873205bfef95767f96..a1749bcb6881930fbef87197b1b40410e40cff07 100644
--- a/ash/system/user/user_view.h
+++ b/ash/system/user/user_view.h
@@ -86,14 +86,14 @@ class UserView : public views::View,
   bool is_user_card_button_;
 
   views::View* logout_button_;
-  scoped_ptr<PopupMessage> popup_message_;
-  scoped_ptr<views::Widget> add_menu_option_;
+  std::unique_ptr<PopupMessage> popup_message_;
+  std::unique_ptr<views::Widget> add_menu_option_;
 
   // False when the add user panel is visible but not activatable.
   bool add_user_enabled_;
 
   // The mouse watcher which takes care of out of window hover events.
-  scoped_ptr<views::MouseWatcher> mouse_watcher_;
+  std::unique_ptr<views::MouseWatcher> mouse_watcher_;
 
   // The focus manager which we use to detect focus changes.
   views::FocusManager* focus_manager_;