Maximum ring buffer size is based on the maxBufferLength of
the system. Also includes a sample for testing upload pressure.
Bug: skia:8243
Change-Id: I36863b725ba9cbcb02d575b2ab9695d186fcd529
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/232759
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
