Unit tests for BaseSessionController

This CL adds unit tests for BaseSessionController.

Also, when ending session, call SessionManager.endCurrentSession()
instead of selecting the default route. Also the app ID is set to null.

Bug: 711860
Change-Id: I002d69c16b72fd68d5ff9076624c74e63f0b0003
Reviewed-on: https://chromium-review.googlesource.com/c/1317337
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Zhiqiang Zhang <zqzhang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607104}
6 files changed