Return empty array from GetBackwardItems and GetForwardItems during session restoration.

This will prevent showing Back And Forward items in the app UI.

Bug: 877671
Change-Id: I93f7868847a58e82d70fc01ebfb11a3a7d30399a
Reviewed-on: https://chromium-review.googlesource.com/c/1356982
Reviewed-by: Danyao Wang <danyao@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613369}
2 files changed