Add source annotations for breakpoints.

runtime/observatory/lib/src/service/object.dart

 // Copyright (c) 2014, 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 service;
 
 /// Helper function for canceling a Future<StreamSubscription>.
 Future cancelFutureSubscription(
     Future<StreamSubscription> subscriptionFuture) async {
   if (subscriptionFuture != null) {
@@ skipping 2706 matching lines @@
     String source = getLine(line).text;
 
     var pos = column;
     if (pos >= source.length) {
       return null;
     }
 
     var c = source.codeUnitAt(pos);
     if (c == 123) return 1; // { - Map literal
 
-    if (c == 91) return 1; // [ - List literal, index, index assignment
+    if (c == 91) return 1;  // [ - List literal, index, index assignment
+
+    if (c == 40) return 1;  // ( - Closure call
 
     if (_isOperatorChar(c)) {
       while (++pos < source.length &&
              _isOperatorChar(source.codeUnitAt(pos)));
       return pos - column;
     }
 
     if (_isInitialIdentifierChar(c)) {
       while (++pos < source.length &&
              _isIdentifierChar(source.codeUnitAt(pos)));
@@ skipping 1080 matching lines @@
     var v = list[i];
     if ((v is ObservableMap) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is ObservableList) {
       _upgradeObservableList(v, owner);
     } else if (v is ObservableMap) {
       _upgradeObservableMap(v, owner);
     }
   }
 }