These are the foundation for the back layer functionality. The behavior
does the heavy lifting to measure the adjacent content view.
As of now this only lays out the views correctly in the hidden state, it doesn't support exposing the back layer at all, yet. Full of TODOs, this is just a skeleton.
PiperOrigin-RevId: 156334640
- Not restoring elevation
- Not restoring on min-height with status bar insets
- Not restoring when expanded="true" set in layout
Test: included
BUG: 33471543
BUG: 33510949
BUG: 33511540
Change-Id: I43b2afeaf1c2cebf0a87045314830064554e2c5d
PiperOrigin-RevId: 148701728
