Revert "Revert "Support multiple DOM isolates and tweak devtools frontend to better handle large #s…

LayoutTests/dart/Multiscript.dart

Index: LayoutTests/dart/Multiscript.dart
diff --git a/LayoutTests/dart/Multiscript.dart b/LayoutTests/dart/Multiscript.dart
index 5d7237607e4a0f53e11890a0627cf6818364d80c..d00b40f99e209cdde4a966b1fb08e9c21b2bdd39 100644
--- a/LayoutTests/dart/Multiscript.dart
+++ b/LayoutTests/dart/Multiscript.dart
@@ -4,19 +4,21 @@
 
 // Dart test for testing isolation across multiple script tags.
 library multiscript;
-import 'dart:async';
+import 'dart:js' as js;
 
 class State {
-  static int s = 0;
-  static _update() { s++; }
-  static int record(int value) {
-      _update();
-    _results.add(value);
-    if (_results.length == 4) {
-      _completer.complete(_results);
-    }
+  // Static stored in Dart so there is a unique value in each Dart DOM isolate.
+  static int sDart = 0;
+  static update() {
+    sDart++;
+    js.context['sJs']++;
+  }
+
+  // Static stored on the JS side of the world so there is one value for it
+  // across all Dart DOM isolates.
+  static int get sJs => js.context['sJs'];
+
+  static registerCallback(int index, Function callback) {
+    js.context.callMethod('registerCallback', [index, callback]);
   }
-  static final _completer = new Completer();
-  static final _results = new List();
-  static Future<List<int>> result = _completer.future;
 }