Reland "Revert "Simplify SkTypeface::charsToGlyphs API to require UTF32 input""

This reverts commit 652b007a4cbb0b8c716510949456243573129ff4.

Reason for revert: Potentially causing Google3 errors

Original change's description:
> Revert "Revert "Simplify SkTypeface::charsToGlyphs API to require UTF32 input""
> 
> with legacy guard for google3
> 
> Needs this to land first: https://critique.corp.google.com/#review/243924283
> 
> This reverts commit 70ed05e53ad244b3234415b447e5fcd53fb40e3b.
> 
> Change-Id: I3e821dfcdbf3004382092338ebad7cceaf40cefd
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208668
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Mike Reed <reed@google.com>
> Auto-Submit: Mike Reed <reed@google.com>

TBR=fmalita@chromium.org,reed@google.com

Change-Id: Id2b3ed8a6157b5e33721b0c5168c5680bfac15b0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208669
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
27 files changed