Add GrDDLTask::dump method

Change-Id: I763db23e200a359b8eae3514c9cd244f358ea3c2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/350605
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed