move setshader to sk_sp, re-using SK_SUPPORT_LEGACY_CREATESHADER_PTR

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1829303002

Review URL: https://codereview.chromium.org/1829303002
33 files changed