Initial layout of selection toolbar.

The initial selection toolbar related architecture. Render service
part and the implementation will be revised in the follow up changes.

Bug: 190030331
Bug: 205822301
Test: manual. Can boot to home and get manager successfully.
Ignore-AOSP-First: new file for T

Change-Id: Iab5d5f2e5e48e6258a63fb0c479194c958ea61e8