[skottie] Add resize-to-fit text alignment extension

Introduce a new SkottieShaper VAlign option (kResizeToFit), to scale the text
size for the best box fit.

The basic idea is to perform a binary search on the font size, until
the shaped text fits snuggly within the specified box.  The search is
focused on height, as horizontal fitting is assumed to be handled in
SkShaper.

Change-Id: I56269e02dda7a34e4ef3b79c205ea651b909f370
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212962
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed