Introduce NavigationSimulator::ReadyToCommit().

Adds one intermediary state to the NavigationSimulator. It corresponds
to the point the navigation is ready to be committed in a renderer.

Bug: 728571
Change-Id: Id7c825510b1ee18ba4c3a52c72f9312f34b21ef7
Reviewed-on: https://chromium-review.googlesource.com/604799
Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#493693}
3 files changed