GitLab

Add NavigationCallback.onFirstContentfulPaint variant that matches up to CCT's version for easier comparison.

Bug: 1152600
Change-Id: I3025464676ecb2cc649e445701cdc5797e4d068d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2559285Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833811}