fix webui for sdk 0.8.7

lib/src/utils_observe.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.
 
 library web_ui.src.utils_observe;
 
+import 'dart:async';
 import 'dart:collection';
-import 'dart:isolate';
 
 // TODO(jmesserly): helpers to combine hash codes. Reuse these from somewhere.
 hash2(x, y) => x.hashCode * 31 + y.hashCode;
 
 hash3(x, y, z) => hash2(hash2(x, y), z);
 
 hash4(w, x, y, z) => hash2(hash2(w, x), hash2(y, z));
 
-// TODO(jmesserly): replace with something in dart:async, as long as it is based
-// on window.setImmediate/mutation observers/postMessage and not setTimeout(0)
-// Maybe we can use Future.value? We need it to be fast (next microtask)
-// like this though: http://dartbug.com/8757.
-/**
- * Adds an event to call [callback], so the event loop will call this after the
- * current stack has unwound.
- */
-void setImmediate(void callback()) {
-  var port = new ReceivePort();
-  port.receive((msg, sendPort) {
-    port.close();
-    callback();
-  });
-  port.toSendPort().send(null);
-}
-
 class Arrays {
   static void copy(List src, int srcStart,
                    List dst, int dstStart, int count) {
     if (srcStart == null) srcStart = 0;
     if (dstStart == null) dstStart = 0;
 
     if (srcStart < dstStart) {
       for (int i = srcStart + count - 1, j = dstStart + count - 1;
            i >= srcStart; i--, j--) {
         dst[j] = src[i];
@@ skipping 17 matching lines @@
       String message = "$start + $length must be in the range [0..${a.length})";
       throw new RangeError(message);
     }
   }
 }
 
 // TODO(jmesserly): bogus type to workaround spurious VM bug with generic base
 // class and mixins.
 abstract class IterableWorkaround extends IterableBase<dynamic> {}
 abstract class ListMixinWorkaround extends ListMixin<dynamic> {}