The idea of the remotely hosted new tab page is to move more functionality out of a privileged context to a web context, using web technologies to help us. As such, a lot of functionality is moving to the "client-side". As a reflection of that, we are replacing the current NewTabUtils.jsm and upcoming AboutNewTab.jsm with a new module. This module will observe to History events, as per NewTabUtils.jsm, as well as some pref changes, to keep sync functionality working. This module will re-use NewTabUtils.jsm's PlacesProvider, however it will send the raw data, i.e. top 100 frecent sites, to the remotely hosted page. DirectoryLinksProvider.jsm will cease to exist and will be moved to the remotely hosted page, the download functionality handled by a service worker.

Repurposing this bug, as it's being broken down. AboutNewTabUtils.jsm will be the central point of contact with the content processes. It will either receive method invocations from multiple observers, or from content processes and will marshal the communications with those objects.