SkFontData to use smart pointers.

The SkFontData type is not exposed externally, so any method which uses
it can be updated to use smart pointers without affecting external
users. Updating this first will make updating the public API much
easier.

This also updates SkStreamAsset* SkStream::NewFromFile(const char*) to
std::unique_ptr<SkStreamAsset> SkStream::MakeFromFile(const char*). It
appears that no one outside Skia is currently using SkStream::NewfromFile
so this is a good time to update it as well.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2339273002

Review-Url: https://codereview.chromium.org/2339273002
40 files changed