Fix error caught by analyzer

sdk/lib/developer/timeline.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.developer;
 
 typedef dynamic TimelineSyncFunction();
 
 /// Add to the timeline.
 class Timeline {
@@ skipping 23 matching lines @@
     var block = _stack.removeLast();
     // Close it.
     block.close();
   }
 
   /// A utility method to time a synchronous [function]. Internally calls
   /// [function] bracketed by calls to [startSync] and [finishSync].
   static dynamic timeSync(String name,
                           TimelineSyncFunction function,
                           {Map arguments}) {
-    beginSync(name, arguments: arguments);
+    startSync(name, arguments: arguments);
     try {
       return function();
     } finally {
       finishSync();
     }
   }
 
   static final List<_SyncBlock> _stack = new List<_SyncBlock>();
 }
 
@@ skipping 39 matching lines @@
 
 /// Returns the current value from the trace clock.
 external int _getTraceClock();
 
 /// Reports a complete synchronous event.
 external void _reportCompleteEvent(int start,
                                    int end,
                                    String category,
                                    String name,
                                    String argumentsAsJson);