Update prefetch thumbnail download metrics
With the change to have an earlier attempt at downloading thumbnails for
prefetched articles, the completeness metric that was in place became
imprecise by mixing results from both attempts in the same buckets. This
change address that by adding more values to the existing tracking enum
that differentiate each of the attempts.
There also some minor, related changes to thumbnail fetching and
histogram testing.
Bug: 794828
Change-Id: Ife84446aa3083d4d21cc1e2713fdf5f6d65ec82e
Reviewed-on: https://chromium-review.googlesource.com/1053355
Commit-Queue: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560429}
CrOS-Libchrome-Original-Commit: e4d10fd312fb132c5ac2cf14b19e9e9e077ef506
1 file changed