Cookie Store: Expand CookieChangeDispatcher's unit tests.

Bug: 729800
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I57c1ec0fbb6ec96164376d63c3cb5cfc30b5a610
Reviewed-on: https://chromium-review.googlesource.com/943402
Reviewed-by: Randy Smith <rdsmith@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540323}
5 files changed