Implement SkFontMgr::onMakeFromFontData in subclasses.

The current serialization format for variations stores only the values
(without the axis names) and relies on the order of the axes for
deserialization. Even after this deficiency is corrected, it will still
be needed for legacy skps.

Add a real test which ensures variable font printing works correctly
in Chromium. The old test was essentially testing MakeFromFontData
against itself instead of creating a font with variations as a user
would.

Bug: chromium:1070089
Change-Id: Ia6eaac91b2ac58795b7ba61c2b52b2f22ef079bd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/299457
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>
3 files changed