Won't this patchset regress a lot (starting from many CEF versions) by making DCompositionCreateDevice / DCompositionCreateDevice2 succeed now without actual implementation? I think now many CEF flavours call that but fallback to other ways of rendering when that fails.
If that is the case, maybe it is best to get the dxgi.CreateSwapchainForComposition implementation first which I guess is potentially most problematic for basic dcomp support?