changed vertex attribute precisions to be actual types

Bug: skia:
Change-Id: Ic5555d9f1be7f24655bdea9f2a3677bfb128ef70
Reviewed-on: https://skia-review.googlesource.com/50221
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
24 files changed