This introduces a pragma: no cover, which is unfortunate.
But this is a prerequisite for removing rietveld support
entirely from the recipe engine without having to do
manual recipe rolls. The entire block of uncovered code
will be removed shortly.

Bug: 770408
Change-Id: I37319f3ae70413adcda655c443325bccffe695d8
Reviewed-on: https://chromium-review.googlesource.com/834455Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>