Adding event delegation.

tests/html/streams_test.dart

 library streams_test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:async';
 import 'dart:html';
 
 class StreamHelper {
   var _a;
   StreamHelper() {
     _a = new TextInputElement();
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       ++callCountOne;
     });
     helper.pulse();
     expect(callCountOne, 1);
 
     subscription.onData(null);
     helper.pulse();
     expect(callCountOne, 1);
   });
 
+  test('forTargets', () {
+    var a = new StreamHelper();
+    var b = new StreamHelper();
+
+    var aTriggered = false;
+    var bTriggered = false;
+    Element.focusEvent.forTargets([a.element, b.element]).listen((e) {
+      if (e.target == a.element) {
+        aTriggered = true;
+      } else if (e.target == b.element) {
+        bTriggered = true;
+      } else {
+        expect(false, true, reason: 'Event for unrecognized element');
+      }
+    });
+
+    a.pulse();
+    expect(aTriggered, true);
+    expect(bTriggered, false);
+
+    b.pulse();
+    expect(aTriggered, true);
+    expect(bTriggered, true);
+  });
+
   var stream = new StreamHelper().stream;
   // Streams have had some type-checking issues, these tests just validate that
   // those are OK.
   test('first', () {
     stream.first.then((_) {});
   });
 
   test('asBroadcastStream', () {
     stream.asBroadcastStream().listen((_) {});
   });
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   });
 
   test('singleMatching', () {
     stream.singleMatching((_) => true).then((_) {});
   });
 
   test('elementAt', () {
     stream.elementAt(0).then((_) {});
   });
 }