Make sure to visit clips and dst proxies during gather

Bug: skia:7190
Change-Id: I0cd4f7734047550c7904f44892ef266498842e0c
Reviewed-on: https://skia-review.googlesource.com/77940
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed