Add dart:io view to the observatory.

runtime/bin/service_object_patch.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.
 
 
 final Map _servicePathMap = {
   'http' : {
     'servers' : _httpServersServiceObject
   }
 };
 
 String _serviceObjectHandler(List<String> paths,
                              List<String> keys,
                              List<String> values) {
   assert(keys.length == values.length);
   badPath() {
     throw "Invalid path '${paths.join("/")}'";
   }
   if (paths.isEmpty) {
-    badPath();
+    return JSON.encode(_ioServiceObject());
   }
   int i = 0;
   var current = _servicePathMap;
   do {
     current = current[paths[i]];
     i++;
   } while (i < paths.length && current is Map);
   if (current is! Function) {
     badPath();
   }
   var query = new Map();
   for (int i = 0; i < keys.length; i++) {
     query[keys[i]] = values[i];
   }
   return JSON.encode(current(paths.sublist(i)));
 }
 
+Map _ioServiceObject() {
+  return {
+    'id': 'io',
+    'type': 'IO',
+    'name': 'io',
+    'user_name': 'io',
+  };
+}
+
 Map _httpServersServiceObject(args) {
   if (args.length == 1) {
     var server = _HttpServer._servers[int.parse(args.first)];
     if (server == null) {
       return {};
     }
     return server._toJSON(false);
   }
   return {
     'id': 'io/http/servers',
     'type': 'HttpServerList',
     'members': _HttpServer._servers.values
         .map((server) => server._toJSON(true)).toList(),
   };
 }