vrwm: Add support for multiple independent displays
This doesn't change much, just splits ShellView and shuffles code
around.
Display-related things go into DisplayView - everything related to
processing and drawing buffers, hit detection, visibility.
ShellView retains overall state management, touchpad, controller and
is the initial recipient of all incoming frames
The composer library is modified to accept and pass multiple displays
Bug: 35996499
Test: Works for the existing single-display output
Change-Id: Ied5061b4dad9e7d68bb187bf86c3d0f2f3b7a55e
11 files changed