OzoneDisplay: Simplify the construction of EventConverter.

With recent changes, we only construct EventConverter and ChannelHost in
InitializeDispatcher. The logic to do this could be simplified by moving
the respective constructions to Get and Realize AcceleratedWidget function
calls.
Introduce SurfaceFactoryWayland which implements SurfaceFactoryOzone.

Currently OzoneDisplay implements SurfaceFactoryOzone interface, responsible
for initializing Event Converters, DisplayChannel etc. This CL introduces
SurfaceFactoryWayland which implements SurfaceFactoryOzone interface.
Most of the implementation is taken from OzoneDisplay or depend on
it. SurfaceFactoryWayland will be taken into use in follow up patch.
OzoneDisplay: Take SurfaceFactoryWayland into use.

This CL takes SurfaceFactoryWayland in to use. Most of the changes in Ozone-
Display are removing obsolete code, code re-arrangement to group relevant
functions together.