Make the repeating argument to timers optional.

runtime/bin/file_impl.dart

Index: runtime/bin/file_impl.dart
diff --git a/runtime/bin/file_impl.dart b/runtime/bin/file_impl.dart
index 3a72b9ae1a67c7f43acd7201bfc3e41db3e72ff1..60eef959111f01d46c62ccc72cb3c9e9b47f6c2f 100644
--- a/runtime/bin/file_impl.dart
+++ b/runtime/bin/file_impl.dart
@@ -97,11 +97,11 @@ class _FileInputStream implements FileInputStream {
     if (!_closed) {
       if (available() > 0) {
         if (_scheduledDataCallback == null) {
-          _scheduledDataCallback = new Timer(issueDataCallback, 0, false);
+          _scheduledDataCallback = new Timer(issueDataCallback, 0);
         }
       } else if (!_eof) {
         if (_scheduledCloseCallback == null) {
-          _scheduledCloseCallback = new Timer(issueCloseCallback, 0, false);
+          _scheduledCloseCallback = new Timer(issueCloseCallback, 0);
           _eof = true;
         }
       }