Include the awaiter stack trace in the service protocol

runtime/observatory/tests/service/awaiter_async_stack_contents_test.dart

+// Copyright (c) 2017, 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=--error_on_bad_type --error_on_bad_override  --verbose_debug
+
+import 'dart:developer';
+import 'package:observatory/models.dart' as M;
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'service_test_common.dart';
+import 'test_helper.dart';
+
+const LINE_C = 19;
+const LINE_A = 24;
+const LINE_B = 30;
+
+foobar() async {
+  debugger();
+  print('foobar'); // LINE_C.
+}
+
+helper() async {
+  debugger();
+  print('helper'); // LINE_A.
+  await foobar();
+}
+
+testMain() {
+  debugger();
+  helper(); // LINE_B.
+}
+
+var tests = [
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(LINE_B),
+  (Isolate isolate) async {
+    ServiceMap stack = await isolate.getStack();
+    // No awaiter frames because we are in a completely synchronous stack.
+    expect(stack['awaiterFrames'], isNull);
+  },
+  resumeIsolate,
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(LINE_A),
+  (Isolate isolate) async {
+    ServiceMap stack = await isolate.getStack();
+    // No awaiter frames because there is no awaiter.
+    expect(stack['awaiterFrames'], isNull);
+  },
+  resumeIsolate,
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(LINE_C),
+  (Isolate isolate) async {
+    // Verify awaiter stack trace is the current frame + the awaiter.
+    ServiceMap stack = await isolate.getStack();
+    expect(stack['awaiterFrames'], isNotNull);
+    List awaiterFrames = stack['awaiterFrames'];
+    expect(awaiterFrames.length, greaterThanOrEqualTo(4));
+    // Awaiter frame.
+    expect(await awaiterFrames[0].toUserString(),
+        stringContainsInOrder(['foobar', '.dart:19']));
+    // Awaiter frame.
+    expect(await awaiterFrames[1].toUserString(),
+        stringContainsInOrder(['helper', '.dart:25']));
+    // Suspension point.
+    expect(awaiterFrames[2].kind, equals(M.FrameKind.asyncSuspensionMarker));
+    // Causal frame.
+    expect(await awaiterFrames[3].toUserString(),
+        stringContainsInOrder(['testMain', '.dart:30']));
+  },
+];
+
+main(args) =>
+    runIsolateTestsSynchronous(args, tests, testeeConcurrent: testMain);