Log the presence of crash reports after running Chrome.

BUG=907979

Change-Id: I8922218a0488eee539a5f3814de3dee9c58e31e0
Reviewed-on: https://chromium-review.googlesource.com/c/1349339
Commit-Queue: Greg Thompson <grt@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610600}