Remove AsyncError with Expando.

tests/standalone/io/http_content_length_test.dart

 // Copyright (c) 2013, 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.
 
 import "package:expect/expect.dart";
 import "dart:isolate";
 import "dart:io";
 
 void testNoBody(int totalConnections, bool explicitContentLength) {
   var errors = 0;
   HttpServer.bind("127.0.0.1", 0, totalConnections).then((server) {
     server.listen(
         (HttpRequest request) {
           Expect.equals("0", request.headers.value('content-length'));
           Expect.equals(0, request.contentLength);
           var response = request.response;
           response.contentLength = 0;
           response.done
             .then((_) {
               Expect.fail("Unexpected successful response completion");
             })
-            .catchError((e) {
-              Expect.isTrue(e.error is HttpException);
+            .catchError((error) {
+              Expect.isTrue(error is HttpException);
             });
           // write with content length 0 closes the connection and
           // reports an error.
           response.write("x");
           // Subsequent write are ignored as there is already an
           // error.
           response.write("x");
           // After an explicit close, write becomes a state error
           // because we have said we will not add more.
           response.close();
           Expect.throws(() => response.write("x"),
                         (e) => e is StateError);
         },
         onError: (e) {
-          Expect.fail("Unexpected server error $e");
+          String msg = "Unexpected server error $e";
+          var trace = getAttachedStackTrace(e);
+          if (trace != null) msg += "\nStackTrace: $trace";
+          Expect.fail(msg);
         });
 
     int count = 0;
     HttpClient client = new HttpClient();
     for (int i = 0; i < totalConnections; i++) {
       client.get("127.0.0.1", server.port, "/")
           .then((request) {
             if (explicitContentLength) {
               request.contentLength = 0;
             }
             return request.close();
           })
           .then((response) {
             Expect.equals("0", response.headers.value('content-length'));
             Expect.equals(0, response.contentLength);
             response.listen(
                 (d) {},
                 onDone: () {
                   if (++count == totalConnections) {
                     client.close();
                     server.close();
                   }
                 });
           })
           .catchError((e) {
-            Expect.fail("Unexpected error $e");
-          });
+            String msg = "Unexpected error $e";
+            var trace = getAttachedStackTrace(e);
+            if (trace != null) msg += "\nStackTrace: $trace";
+            Expect.fail(msg);
+         });
     }
   });
 }
 
 void testBody(int totalConnections, bool useHeader) {
   HttpServer.bind("127.0.0.1", 0, totalConnections).then((server) {
     int serverCount = 0;
     server.listen(
         (HttpRequest request) {
           Expect.equals("2", request.headers.value('content-length'));
           Expect.equals(2, request.contentLength);
           var response = request.response;
           if (useHeader) {
             response.contentLength = 2;
           } else {
             response.headers.set("content-length", 2);
           }
           request.listen(
               (d) {},
               onDone: () {
                 response.write("x");
                 Expect.throws(() => response.contentLength = 3,
                               (e) => e is HttpException);
                 response.write("x");
                 response.write("x");
                 response.done
                     .then((_) {
                       Expect.fail("Unexpected successful response completion");
                     })
-                    .catchError((e) {
-                      Expect.isTrue(e.error is HttpException, "[$e]");
+                    .catchError((error) {
+                      Expect.isTrue(error is HttpException, "[$error]");
                       if (++serverCount == totalConnections) {
                         server.close();
                       }
                     });
                 response.close();
                 Expect.throws(() => response.write("x"),
                               (e) => e is StateError);
               });
         },
-        onError: (e) => Expect.fail("Unexpected error $e"));
+        onError: (e) {
+          String msg = "Unexpected error $e";
+          var trace = getAttachedStackTrace(e);
+          if (trace != null) msg += "\nStackTrace: $trace";
+          Expect.fail(msg);
+        });
 
     int clientCount = 0;
     HttpClient client = new HttpClient();
     for (int i = 0; i < totalConnections; i++) {
       client.get("127.0.0.1", server.port, "/")
           .then((request) {
             if (useHeader) {
               request.contentLength = 2;
             } else {
               request.headers.add(HttpHeaders.CONTENT_LENGTH, "7");
@@ skipping 44 matching lines @@
                 Expect.throws(
                     () => response.headers.chunkedTransferEncoding = false,
                     (e) => e is HttpException);
                 response.write("x");
                 response.write("x");
                 response.close();
                 Expect.throws(() => response.write("x"),
                               (e) => e is StateError);
               });
         },
-        onError: (e) => Expect.fail("Unexpected error $e"));
+        onError: (e) {
+          String msg = "Unexpected error $e";
+          var trace = getAttachedStackTrace(e);
+          if (trace != null) msg += "\nStackTrace: $trace";
+          Expect.fail(msg);
+        });
 
     int count = 0;
     HttpClient client = new HttpClient();
     for (int i = 0; i < totalConnections; i++) {
       client.get("127.0.0.1", server.port, "/")
           .then((request) {
             if (useHeader) {
               request.contentLength = 2;
               request.headers.chunkedTransferEncoding = true;
             } else {
@@ skipping 12 matching lines @@
             Expect.equals(-1, response.contentLength);
             response.listen(
                 (d) {},
                 onDone: () {
                   if (++count == totalConnections) {
                     client.close();
                     server.close();
                   }
                 });
           })
-          .catchError((e) => Expect.fail("Unexpected error $e"));
+          .catchError((e) {
+            String msg = "Unexpected error $e";
+            var trace = getAttachedStackTrace(e);
+            if (trace != null) msg += "\nStackTrace: $trace";
+            Expect.fail(msg);
+          });
     }
   });
 }
 
 void testSetContentLength() {
   HttpServer.bind().then((server) {
     server.listen(
         (HttpRequest request) {
           var response = request.response;
           Expect.isNull(response.headers.value('content-length'));
@@ skipping 21 matching lines @@
 
 void main() {
   testNoBody(5, false);
   testNoBody(5, true);
   testBody(5, false);
   testBody(5, true);
   testBodyChunked(5, false);
   testBodyChunked(5, true);
   testSetContentLength();
 }