Extend empty document check to check for meta-only data

An empty document is one which contains no 'real' data, so
we should check for meta-only documents when deciding whether
to add in a wrapper paragraph.

Bug: 50289
Change-Id: Ib3ebf0717aa0c6c51fd1d0b14e95de50b2842647
Merge "Extend empty document check to check for meta-only data"