Implement intent to uri mapping for slices

This adds the notion of creating a slice based on an intent. To use this
developers can implement onMapIntentToUri and return a uri based on the
intent. This enables SliceView to be populated via an intent.

Test: to be added...
Change-Id: I2abd861f2a3dff80ab8b6492a5c3205bc891d19c
6 files changed