When opting into the Skia renderer, we default to metal on macOS and D3D on Windows.
However if you want to develop a cross-platform application with Skia and
for example rely on OpenGL to be able to implement an OpenGL underlay or overlay,
then we need the ability to explicitly opt into skia's GL renderer.
cc #1445
This reverts commit 7f2868b5a0.
This is still causing issues on Windows, as reported by tay64 on
Mattermost. This is a box (no vmware) with an ATI driver.
Vendor: ATI Technologies Inc.
Version: 4.6.14761 Core Profile Forward-Compatible Context 21.30.23.04 30.0.13023.4001
