Consolidate gathering of info from GL strings.

Should not change functionality.

Bug: 1203705
Change-Id: I2a17fb0ccb729033c964a138dbd5e86be7f93d9e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/405200
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
7 files changed