The 1x1 keep-alive repaint loop was extended to Windows in a87aa296 to
paper over the legacy compositing path's resize desync (#227); the DComp
rework replaced that presentation path entirely. On the DComp engine the
100ms repaints become DirectComposition commits during playback, and
once fullscreen focus engages VRR (FreeSync/G-Sync) every commit forces
a scanout off the video's cadence - the micro-stutter of #1707.
The widget now owns the platform decision behind a test seam, and a new
quiescence test pins the hidden-chrome player UI to zero scheduled
frames so no future ticker can silently reintroduce the defect.
edde746