mozilla/servo — pull request #2520 by saneyuki (2014-05-30 18:36:33+00:00)
Title: Remove needless '&mut self' from DOM type methods

Related #2514

- This removes needless '&mut self's from some DOM type method simply.
- This doesn't include some DOM Types which have basis method called from other types (e.g. `Element`). We still have to need to open their changes.
- This does not include to remove an implicit `deref_mut()`.