Revert "Unify dart:isolate."

lib/isolate/timer.dart

Index: lib/isolate/timer.dart
diff --git a/lib/isolate/timer.dart b/lib/isolate/timer.dart
index 76f98a1c2cd610ed00ffdbb84d6a6c1b65be3363..95de18eb3b1c12b064f689f8e96bdcb95d2a8cc0 100644
--- a/lib/isolate/timer.dart
+++ b/lib/isolate/timer.dart
@@ -20,34 +20,3 @@ interface Timer default _TimerFactory {
    */
   void cancel();
 }
-
-// TODO(ajohnsen): Patch timer once we have support for patching named
-//                 factory constructors in the VM.
-
-typedef Timer _TimerFactoryClosure(int milliSeconds,
-                                   void callback(Timer timer),
-                                   bool repeating);
-
-// _TimerFactory provides a hook which allows various implementations of this
-// library to provide a concrete class for the Timer interface.
-class _TimerFactory {
-  factory Timer(int milliSeconds, void callback(Timer timer)) {
-    if (_factory == null) {
-      throw new UnsupportedOperationException("Timer interface not supported.");
-    }
-    return _factory(milliSeconds, callback, false);
-  }
-
-  factory Timer.repeating(int milliSeconds, void callback(Timer timer)) {
-    if (_factory == null) {
-      throw new UnsupportedOperationException("Timer interface not supported.");
-    }
-    return _factory(milliSeconds, callback, true);
-  }
-
-  static _TimerFactoryClosure _factory;
-}
-
-void _setTimerFactoryClosure(_TimerFactoryClosure closure) {
-  _TimerFactory._factory = closure;
-}