When updating hotseat qsb alpha in response to assistant visiblity
changes, use Hotseat.setQsbAlpha with a designated alpha channel instead
of updating the view alpha directly. QSB alpha can be changed for
different reasons - e.g. because taskbar is shown, so the calling
View.setAlpha directly may overrride visibility set from other sources.
Using setQsbAlpha ensures that the final qsb alpha aggregates all alpha
inputs.
Bug: 413500588
Flag: EXEMPT bugfix
Test: On desktop device (where taskbar is shown on home), connect a
display while on home, and verify the inline hotseat qsb does not
become visible on the primary display.
Change-Id: Ida2325aa630c0c2d2c324d5e3001207cf661f2e9
Toni Barzic
e175eea012