We need to support ui_scale_factor in mustash. Right now we are assuming the following relationship holds true:

pixels = dip * device_scale_factor

This isn't the case when ui_scale_factor != 1. We can now test ui_scale_factor in mustash by hitting Ctrl/Shift/+ (scale up), Ctrl/Shift/- (scale down) or Ctrl/Shift/0 (reset ui_scale_factor to 1). This only works if we are to have an internal display and with dev/debug shortcuts enabled.

# 1x device_scale_factor
/chrome --mash --ash-debug-shortcuts --ash-dev-shortcuts --ash-debug-shortcuts --ash-dev-shortcuts --vmodule=*/ui/display/*=1 --screen-config=1600x900/i

# 2x device_scale_factor
./chrome --mash --ash-debug-shortcuts --ash-dev-shortcuts --ash-debug-shortcuts --ash-dev-shortcuts --vmodule=*/ui/display/*=1 --screen-config=1600x900^300/i

Somewhere in the WS and/or WM we need to handle an additional scale factor.