Make sure each story is independent of each other
Make sure each story is independent of each other

If we close all tabs before running the next story, also set _previous_page
as None to ensure each story is independent of each other.

Bug: chromium:968917
Change-Id: I43fcd3289b3321cd0a7e7a7eb50494d9242c77ee
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/1638236
Reviewed-by: Caleb Rouleau <58bdb6276c01e3ed53e660bf706aa902204feb0d@chromium.org>
Reviewed-by: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult