Remove the dependency on GCE for display size.

Change-Id: I201ffae8193cfcac48a7ad3446f4b79da6c3d217
Reviewed-on: https://swiftshader-review.googlesource.com/4032
Tested-by: Greg Hartman <ghartman@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>