In mus-ws there are currently a number of assumptions where each ws::Display (top-level window) corresponds to a display::Display (display device). These assumptions make sense for internal window mode (Chrome OS) where there is one top level window for each display device. For external window mode (Desktop Chrome) top level windows are Chrome windows. There can be 0-N top level Chrome windows on each display device and our current code won't quite work.
External contributors are starting to work on external window mode and will be blocked by these assumptions soon. Fixing this will require changes in ws::DisplayManager, ws::UserDisplayManager and display::ScreenManager at least.
Comment 1 by bugdroid1@chromium.org, Feb 17 2017
Project Member