tools: separate TimeUtils from AnimTimer

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>
diff --git a/samplecode/SampleHairline.cpp b/samplecode/SampleHairline.cpp
index aafa564..df3b376 100644
--- a/samplecode/SampleHairline.cpp
+++ b/samplecode/SampleHairline.cpp
@@ -22,7 +22,6 @@
 #include "include/utils/SkRandom.h"
 #include "samplecode/Sample.h"
 #include "src/utils/SkUTF.h"
-#include "tools/timer/AnimTimer.h"
 
 static SkRandom gRand;
 
@@ -208,7 +207,7 @@
         canvas->drawBitmap(bm2, SkIntToScalar(10), SkIntToScalar(10), nullptr);
     }
 
-    bool onAnimate(const AnimTimer&) override {
+    bool onAnimate(double /*nanos*/) override {
         if (fDoAA) {
             fProcIndex = cycle_hairproc_index(fProcIndex);
             // todo: signal that we want to rebuild our TITLE