gm, slides, and samples no longer need to know about the implementation
details of AnimTimer.
This
virtual bool onAnimate(const AnimTimer&);
becomes this:
virtual bool onAnimate(double /*nanoseconds*/);
which is much easier to reason about.
AnimTimer itself is now part of viewer.
Change-Id: Ib70bf7a0798b1991f25204ae84f70463cdbeb358
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226838
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>