Add metrics for time from compositor creation to nav commit/RFH swap

This metric will help us see if the surface embedding time
(currently happens at RFH swap) can improve significantly if we
move it to commit time instead.

Change-Id: I63fe66fab1f78d8638cb909c34b791ffae310e01
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5086331
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Rakina Zata Amni <rakina@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1239440}