Fix service test websocket error edge case

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 59 matching lines @@
 
 /// A NetworkRpcException is used to indicate that an rpc has
 /// been canceled due to network error.
 class NetworkRpcException extends RpcException
     implements M.ConnectionException {
   NetworkRpcException(String message) : super(message);
 
   String toString() => 'NetworkRpcException(${message})';
 }
 
+Future<ServiceObject> ignoreNetworkErrors(
+    Object error, [ServiceObject resultOnNetworkError = null]) {
+  if (error is NetworkRpcException) {
+    return new Future.value(resultOnNetworkError);
+  }
+  return new Future.error(error);
+}
+
 class MalformedResponseRpcException extends RpcException {
   MalformedResponseRpcException(String message, this.response) : super(message);
 
   Map response;
 
   String toString() => 'MalformedResponseRpcException(${message})';
 }
 
 class FakeVMRpcException extends RpcException {
   FakeVMRpcException(String message) : super(message);
@@ skipping 303 matching lines @@
   void _update(Map map, bool mapIsRef) {
     if (map['class'] != null) {
       // Sent with refs for some types. Load it if available, but don't clobber
       // it with null for kinds that only send if for full responses.
       clazz = map['class'];
     }
 
     // Load the full class object if the isolate is runnable.
     if (clazz != null) {
       if (clazz.isolate.runnable) {
-        clazz.load();
+        // No one awaits on this request so we silence any network errors
+        // that occur here but forward other errors.
+        clazz.load().catchError((error) => ignoreNetworkErrors(error, clazz));
       }
     }
 
     if (mapIsRef) {
       return;
     }
     size = map['size'];
   }
 }
 
@@ skipping 439 matching lines @@
   }
 
   Future<ServiceObject> getFlagList() {
     return invokeRpc('getFlagList', {});
   }
 
   Future<ServiceObject> _streamListen(String streamId) {
     Map params = {
       'streamId': streamId,
     };
-    return invokeRpc('streamListen', params).catchError((e) {
-      // Ignore network errors on stream listen.
-      if (e is NetworkRpcException) {
-        return null;
-      }
-    });
+    // Ignore network errors on stream listen.
+    return invokeRpc('streamListen', params).catchError(
+        (e) => ignoreNetworkErrors(e));
   }
 
   Future<ServiceObject> _streamCancel(String streamId) {
     Map params = {
       'streamId': streamId,
     };
-    return invokeRpc('streamCancel', params).catchError((e) {
-      // Ignore network errors on stream cancel.
-      if (e is NetworkRpcException) {
-        return null;
-      }
-    });
+    // Ignore network errors on stream cancel.
+    return invokeRpc('streamCancel', params).catchError(
+        (e) => ignoreNetworkErrors(e));
   }
 
   // A map from stream id to event stream state.
   Map<String, _EventStreamState> _eventStreams = {};
 
   // Well-known stream ids.
   static const kVMStream = 'VM';
   static const kIsolateStream = 'Isolate';
   static const kTimelineStream = 'Timeline';
   static const kDebugStream = 'Debug';
@@ skipping 3464 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);
     }
   }
 }