Add the --steal-breakpoints flag.

runtime/observatory/tests/service/steal_breakpoint_test.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.
+// VMOptions=--compile-all --error_on_bad_type --error_on_bad_override --steal-breakpoints
+
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+import 'dart:async';
+
+int counter = 0;
+
+void periodicTask(_) {
+  counter++;  // Line 14.  We set our breakpoint here.
+  if (counter % 1000 == 0) {
+    print('counter = $counter');
+  }
+}
+
+void startTimer() {
+  new Timer.periodic(const Duration(milliseconds:10), periodicTask);
+}
+
+var tests = [
+
+// Add a breakpoint and wait for it to be reached.
+(Isolate isolate) async {
+  await isolate.rootLib.load();
+
+  // Set up a listener to wait for breakpoint events.
+  Completer completer = new Completer();
+  var subscription;
+  subscription = isolate.vm.events.stream.listen((ServiceEvent event) {
+    if (event.eventType == ServiceEvent.kPauseBreakpoint) {
+      print('Isolate paused at breakpoint');
+      subscription.cancel();
+      completer.complete();
+    }
+  });
+
+  // Add the breakpoint.
+  var script = isolate.rootLib.scripts[0];
+  var result = await isolate.addBreakpoint(script, 14);
+  expect(result is Breakpoint, isTrue);
+
+  await completer.future;  // Wait for breakpoint event to fire.
+},
+
+// We are at the breakpoint on line 14.
+(Isolate isolate) async {
+  ServiceMap stack = await isolate.getStack();
+  expect(stack.type, equals('Stack'));
+  expect(stack['frames'].length, greaterThanOrEqualTo(1));
+
+  Script script = stack['frames'][0]['script'];
+  await script.load();
+  expect(script.name,endsWith('steal_breakpoint_test.dart'));
+  expect(script.tokenToLine(stack['frames'][0]['tokenPos']), equals(14));
+},
+
+// Resume
+(Isolate isolate) async {
+  Completer completer = new Completer();
+  var subscription;
+  subscription = isolate.vm.events.stream.listen((ServiceEvent event) {
+    if (event.eventType == ServiceEvent.kResume) {
+      print('Isolate resumed');
+      subscription.cancel();
+      completer.complete();
+    }
+  });
+  isolate.resume();
+  await completer.future;
+},
+
+];
+
+main(args) => runIsolateTests(args, tests, testeeBefore: startTimer);