Separate background & pointer alpha for the expanded view

These will be animated separately for the new animations.

This CL shouldn't cause any visual changes to existing animations.

Test: manual - observe collapse / expand / swipe up to collapse
Test: atest ExpandedViewAnimationControllerTest
Bug: 311450609
Change-Id: I050cdde1c1614c6ac97ad6abb27a427823770178
1 file changed