Mac's GLRenderer currently uses glScheduleCALayerCHROMIUM to construct the CALayer tree from the quad list at [1]

When the GLRenderer is in the GPU process, we can skip going through the command buffer, and update the CALayer tree directly.

It may also be possible to avoid building the DrawingFrame::ca_layer_overlay_list.

[1] https://cs.chromium.org/chromium/src/components/viz/service/display/gl_renderer.cc?rcl=b7c2c4ec1b901041af24793d679e3acaec4b750d&l=3260