This will allow us to select the Impl constructor more easily

 createWindowSurface
 createPbufferSurface
 createPbufferSurfaceFromClientBuffer
 createPixmapSurface

This in turn lets us pass an EGLImplFactory to the constructor and
will allow us to pass in the local SurfaceState to the constructor.

BUG=angleproject:1369

Change-Id: I6b13c1548c54bd5c493d59b68bfdaf55226b6bb5
Reviewed-on: https://chromium-review.googlesource.com/342060Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>