document.close from bool to void

Nothing meaningful is returned, it is inconsistent with the bulk of the rest of skia's api. The C api is waiting on this change as well.

Required chrome CL: https://codereview.chromium.org/2355343003/

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2354403002

Review-Url: https://codereview.chromium.org/2354403002
9 files changed