For Viz to be enabled on Android, we need to add Viz-process setup code to the browser proc. On non-Android platforms this is handled by Swapping GpuProcessTransportFactory for a VizProcessTransportFactory. Unfortunately, Android doesn't use these classes.

Instead, the Android functionality similar to GpuProcessTransportFactory is embedded in CompositorImpl, making it hard to swap this logic out for a Viz version when in Viz mode. We should pull out the relevant code into a helper class / interface. We *may* be able to share some code with GpuProcessTransportFactory, but given the generally simpler Android requirements and the reliance of GpuProcessTransportFactory on ui::Compositor, this may not make sense.