skslc type constructor cleanups

BUG=skia:

Change-Id: I87108b5e107419d99c996ef032eda512a68451ab
Reviewed-on: https://skia-review.googlesource.com/8117
Commit-Queue: Greg Daniel <egdaniel@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
9 files changed