GitLab

While a navigation is pending, show the original URL if the browser is
navigating to the previews server.

Reworks the GetOriginal APIs in the Previews bridge to support a plain-
string impl since checking for a committed preview won't work while the
navigation is pending.

Bug: 894881
Change-Id: Ic8ffd3e16b270dd69efb7a62128265629a5b9de2
Reviewed-on: https://chromium-review.googlesource.com/c/1330761Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: Doug Arnett <dougarnett@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607352}