Bug 1007600 - Support inline activity

https://bugzilla.mozilla.org/show_bug.cgi?id=1007600
If we are going to put `LaunchContext` into `window`, why not just access this object inside `Settings.init` directly ? By doing so, in the future, if there is any subpanels want to know the situation of current activity, they can directly access it from `window.LaunchContext`. 

Or you want to put it as a internal variable and subpanels can access it by something like : `SettingsService.context` ?