Fix causal_async_star_stack_contents_test with optimization-counter-threshold=5

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;
 
 // Some value smaller than the object ring, so requesting a large array
 // doesn't result in an expired ref because the elements lapped it in the
 // object ring.
 const int kDefaultFieldLimit = 100;
@@ skipping 4386 matching lines @@
     description = map['description'];
     vmName = map['name'];
     value = map['value'];
     min = map['min'];
     max = map['max'];
   }
 
   String toString() => "ServiceMetric($_id)";
 }
 
+void printFrames(List<Frame> frames) async {
+  for (int i = 0; i < frames.length; i++) {
+    final Frame frame = frames[i];
+    String frameText = await frame.toUserString();
+    print('#${i.toString().padLeft(3)}: $frameText');
+  }
+}
+
 class Frame extends ServiceObject implements M.Frame {
   M.FrameKind kind = M.FrameKind.regular;
   int index;
   ServiceFunction function;
   SourceLocation location;
   Code code;
   List<ServiceMap> variables = <ServiceMap>[];
   String marker;
 
   Frame._empty(ServiceObject owner) : super._empty(owner);
@@ skipping 26 matching lines @@
 
   String toString() {
     if (function != null) {
       return "Frame([$kind] ${function.qualifiedName} $location)";
     } else if (location != null) {
       return "Frame([$kind] $location)";
     } else {
       return "Frame([$kind])";
     }
   }
+
+  String toUserString() async {
+    if (function != null) {
+      return "Frame([$kind] ${function.qualifiedName} "
+             "${await location.toUserString()})";
+    } else if (location != null) {
+      return "Frame([$kind] ${await location.toUserString()}";
+    } else {
+      return "Frame([$kind])";
+    }
+  }
 }
 
 class ServiceMessage extends ServiceObject {
   int index;
   String messageObjectId;
   int size;
   ServiceFunction handler;
   SourceLocation location;
 
   ServiceMessage._empty(ServiceObject owner) : super._empty(owner);
@@ skipping 91 matching lines @@
     var v = list[i];
     if ((v is Map) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is List) {
       _upgradeList(v, owner);
     } else if (v is Map) {
       _upgradeMap(v, owner);
     }
   }
 }