SDA: Update start time if layout change detected during snapshot update.

This addresses the problem where a vertical resize does not trigger
style and layout.  With this change we catch the layout inconsistency
during the snapshot update and recalculate a new start time.



Bug: 1447321
Change-Id: I8985f66233ff96f1b359c9a0f6aeee3525082111
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4566235
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149163}