SkPDF: Add sk_sp setters; .release() becomes std::move()

Note to reviewers:  Start with changes to SkPDFTypes.h

Many places that had a bare pointer owning a reference are refactored to
use a sk_sp.

There remain several places where a non-owning pointer `T*` should be
replaced with `const sk_sp<T>&` to eliminate the common pattern
`sk_sp<T>(SkRef(x))`.

Committed: https://skia.googlesource.com/skia/+/9904c9212074279380e21f96575078734dbbd308
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1775043002

Review URL: https://codereview.chromium.org/1775043002

0 files changed, 0 insertions, 0 deletions