Reland "Remove SkTime from the public API"

This reverts commit bd391577d4a62f3a7bf633817f4a8f5b9aa3f1ee.

Reason for revert: Should not have been reverted, previous issue was fixed

Original change's description:
> Revert "Remove SkTime from the public API"
>
> This reverts commit a0572041af8e5317da14dd8fced3c72196545abb.
>
> Reason for revert: causing Google3 breakage
> https://fusion2.corp.google.com/triage/615500517562051498/10304141939179520/invocations/0e55b3cd-e449-411e-8c56-61adc92f6f0d/targets/%2F%2Fjavatests%2Fcom%2Fgoogle%2Fandroid%2Fwearable%2Ffitbit%2Fecg%2Fapi:EcgApiFitbitTest/log
>
> Original change's description:
> > Remove SkTime from the public API
> >
> > Change-Id: Ie310d9dad9f22bed5317568b9d862ec58dc3a66e
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/749817
> > Reviewed-by: Herb Derby <herb@google.com>
> > Commit-Queue: Kevin Lubick <kjlubick@google.com>
>
> Change-Id: Ib267ad2b9bacc3cb3093f18912e8779f60bb11cd
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/752276
> Auto-Submit: John Stiles <johnstiles@google.com>
> Reviewed-by: Herb Derby <herb@google.com>
> Commit-Queue: Herb Derby <herb@google.com>

Change-Id: I920bd49424dd98fc577857e9a842d6bb968c3286
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/752201
Owners-Override: Kevin Lubick <kjlubick@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
57 files changed