GitLab

Moves isTabSwitcherActive, dismissingTabSwitcher to SceneController.

Bug: none
Change-Id: If90fd2ee706f42a57433beabc3d564058bada511
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2087401
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748267}