View source for Gaia/System/Contribution

== System App Review/Contribution Notes ==
* Use Service.query/Service.request instead of direct module access like |window.appWindowManager._activeApp|
 * Service.query is for synchronous information check
 * Service.request is to request certain asynchronous action to other module.
Read https://github.com/mozilla-b2g/gaia/blob/master/apps/system/js/service.js for more infomation
* Avoid polluting #screen element anymore. We are having a class disaster now. If your view needs to know whether other's view, try using events and update your own element instead of the high level screen. Clean up bug is here: https://bugzilla.mozilla.org/show_bug.cgi?id=1110659
* Avoid using stopImmediatePropagation to control the event ordering. If you do need it, implement an event priority manager like https://github.com/mozilla-b2g/gaia/blob/master/apps/system/js/hierarchy_manager.js
* Escape HTML before you inject!