GitLab

Implementation for chrome.tabs.goBack and chrome.tabs.goForward
Above APIs provide a reliable way to trigger a navigate-back/forward
action like back/forward button on toolbar.

Bug: 830622
Change-Id: I1f5e8d5e4768161f43b2df1621a03a6cc3383b4f
Reviewed-on: https://chromium-review.googlesource.com/c/1274225Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604831}