GitLab

window list

As discussed - added the window/activity order management functions
to the WindowListProvider and changed the use cases (at least partially).
There are still more things to do, but we might want to do that either
 a. incrementally or
 b. as a separate issue since the associated BUG(388085) has nothing to
    do with this.
Note: This is more work - especially because the code in question is being
worked on actively by others.

BUG=407103
TEST=athena_unittest.SimpleChecks, athena_unittest.TestWindowOrderingFunctions

Review URL: https://codereview.chromium.org/480293003

Cr-Commit-Position: refs/heads/master@{#294103}