Removed IllegalAccessException and UnsupportedOperationException.

lib/isolate/timer.dart

Index: lib/isolate/timer.dart
diff --git a/lib/isolate/timer.dart b/lib/isolate/timer.dart
index 8684de73170fcea61ce6438bfdf5cff3bcc5fd2c..d8da52f7d1a26b4114b5ce5bc2481a212bf74995 100644
--- a/lib/isolate/timer.dart
+++ b/lib/isolate/timer.dart
@@ -9,7 +9,7 @@ abstract class Timer {
    */
   factory Timer(int milliSeconds, void callback(Timer timer)) {
     if (_TimerFactory._factory == null) {
-      throw new UnsupportedOperationException("Timer interface not supported.");
+      throw new UnsupportedError("Timer interface not supported.");
     }
     return _TimerFactory._factory(milliSeconds, callback, false);
   }
@@ -20,7 +20,7 @@ abstract class Timer {
    */
   factory Timer.repeating(int milliSeconds, void callback(Timer timer)) {
     if (_TimerFactory._factory == null) {
-      throw new UnsupportedOperationException("Timer interface not supported.");
+      throw new UnsupportedError("Timer interface not supported.");
     }
     return _TimerFactory._factory(milliSeconds, callback, true);
   }