Dynamically integrate custom data from other apps

[vestrel00]

The native Contacts app (or AOSP Contacts) parses a bunch of xml files coming in from other apps that declare their custom data in xml. This allows external apps to show their custom data within the native Contacts app. We would need to provide an API to do something similar if we want to provide other developers a way to dynamically integrate custom data from other apps without having to explicitly know about them.

This API would be useful in implementing a dynamic list of custom data that follows a certain format in an app. These custom data will be read-only.

This is part of the discussion; #187