Revert "use SkSpan in SkTypeface API"

crashing this:
https://ci.chromium.org/ui/p/chromium/builders/try/android-x86-rel/b8713083105510845153/test-results?q=ExactID%3Aninja%3A%2F%2Fthird_party%2Fblink%2Frenderer%2Fplatform%3Ablink_platform_unittests%2FCachingWordShaperTest.SegmentEmojiSequences+VHash%3A3a546163a7933064&clean=

This reverts commit 706524f3d55b39a82554cdbdaff18e0e7eaa8fe0.

Change-Id: Ibd24178812cad80430118f03ae6eb9c0146dd558
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1002457
Commit-Queue: Mike Reed <mike@reedtribe.org>
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Thomas Smith <thomsmit@google.com>
11 files changed