Revert "Bug 49218: Hide errors in preview output"

Breaks previews, will need further API work.

This reverts commit ee8c429842c5d4dd80b9a85b543f495a8dc6eb88

Change-Id: Ieaa684b03ce57b2e9e64e4e18eb5ee48606cab5b
Merge "Revert "Bug 49218: Hide errors in preview output""