Start Primes logging when app starts.

This CL is part of a multi-CL change:
 - https://crrev.com/c/3947359
 - https://crrev.com/i/5029613
=> https://crrev.com/c/3949729

LOW_COVERAGE_REASON=Add a simple provider api call which will be no-op for production build.

Change-Id: Ic5ce47404f7646c58da5f12cabc7189ebbd3c00c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3949729
Reviewed-by: Ali Juma <ajuma@chromium.org>
Commit-Queue: Max Li <maxqli@google.com>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1058302}