Add ability to dump opList info at flush-time

When debugging DDL it is useful to just see which ops are being drawn instead of the entire reordering history.

Change-Id: I89708fecbd53c097b00e65b0da426bfb8046b0ee
Reviewed-on: https://skia-review.googlesource.com/122780
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
9 files changed