Revert "Add ticks counter to Timer."

runtime/lib/timer_impl.dart

Index: runtime/lib/timer_impl.dart
diff --git a/runtime/lib/timer_impl.dart b/runtime/lib/timer_impl.dart
index fb0dfa897e49dae346c0cb158cb62af63bf1288a..8c0a670abdfdaedafdb94b18d33dc589c7e4e2fa 100644
--- a/runtime/lib/timer_impl.dart
+++ b/runtime/lib/timer_impl.dart
@@ -146,8 +146,6 @@ class _Timer implements Timer {
   var _indexOrNext; // Index if part of the TimerHeap, link otherwise.
   int _id; // Incrementing id to enable sorting of timers with same expiry.
 
-  int _tick = 0; // Backing for [tick],
-
   // Get the next available id. We accept collisions and reordering when the
   // _idCount overflows and the timers expire at the same millisecond.
   static int _nextId() {
@@ -199,8 +197,6 @@ class _Timer implements Timer {
 
   bool get isActive => _callback != null;
 
-  int get tick => _tick;
-
   // Cancels a set timer. The timer is removed from the timer heap if it is a
   // non-zero timer. Zero timers are kept in the list as they need to consume
   // the corresponding pending message.
@@ -367,18 +363,7 @@ class _Timer implements Timer {
           if (!timer._repeating) {
             // Mark timer as inactive.
             timer._callback = null;
-          } else if (timer._milliSeconds > 0) {
-            var ms = timer._milliSeconds;
-            int overdue =
-                VMLibraryHooks.timerMillisecondClock() - timer._wakeupTime;
-            if (overdue > ms) {
-              int missedTicks = overdue ~/ ms;
-              timer._wakeupTime += missedTicks * ms;
-              timer._tick += missedTicks;
-            }
           }
-          timer._tick += 1;
-
           callback(timer);
           // Re-insert repeating timer if not canceled.
           if (timer._repeating && (timer._callback != null)) {