GitLab

This reverts commit f9d8f7f6.

Reason for revert: Apologies, this test seems to be timing out:
https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8913896950441933072/+/steps/browser_tests/0/logs/Deterministic_failure:_TimeToFirstPresentRecorderTest.VerifyTimeCalculated__status_TIMEOUT_/0

Original change's description:
> chromeos: removes time_to_first_present.mojom
> 
> And instead has ash directly access the startup time.
> 
> BUG=958213
> TEST=covered by tests
> TBR=tsepez@chromium.org
> 
> Change-Id: I146c27edef79ff8fb69ca7cdd7f230ad77f040a8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1602854
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Tom Sepez <tsepez@chromium.org>
> Reviewed-by: James Cook <jamescook@chromium.org>
> Commit-Queue: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#658315}

TBR=jamescook@chromium.org,sky@chromium.org,tsepez@chromium.org

Change-Id: I272066f1adc2866821a5195dca1907a6f077069a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 958213
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1605255Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658455}