ChromeOS: Shelf items on 2nd display open V2 apps on wrong display.

On Chrome OS Stable (tested back to M50...)
(1) Connect a second display (or use --ash-host-window-bounds=500x500,600+0-500x500)
(2) Pin the Files app to the shelf (via app list context menu).
(3) Click the Files item on the shelf on the second/external display.
Expected: The Files app opens on the second/external display.
Actual: The Files app opens on the priamry/internal display.

This may be a regression, but it's present in M50, so it's long-standing.
This is limited to V2 apps; doesn't repro with chrome or v1 app windows/tabs.

Discovered while investigating  Issue 768908 .
Perhaps related to WindowSizer/ash::WindowPositioner, see related  Issue 764009 .