Customize construction for each use case.

Bug 26851951

Change-Id: Ic10166bbfeaf11e800fec2a6470446b76e49b825
Reviewed-on: https://swiftshader-review.googlesource.com/4710Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>