SkShaderBase::isAPicture()

motivation: will be used by SkPDF backend in later CL.

Bug: chromium:967418
Change-Id: I1002c290f70245cce7ae2cf759d3eaf54cb8cd81
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/216873
Commit-Queue: Hal Canary <halcanary@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Auto-Submit: Hal Canary <halcanary@google.com>
5 files changed