Revert "Revert "WindowList be gone!""

This reverts commit ffa5a9de0c127cb77ddec625fea101ddddb7ad32.

Bug: 33098800
Bug: 33098294
Test: Existing tests pass.
Change-Id: I5803a010c5a224dd1cf452a4a7beb3a4c0a043f4
14 files changed