Roll polymer to 0.3.5

pkg/template_binding/test/template_binding_test.dart

Index: pkg/template_binding/test/template_binding_test.dart
diff --git a/pkg/template_binding/test/template_binding_test.dart b/pkg/template_binding/test/template_binding_test.dart
index 375d3d64e8e8d0e59af191952daf8fc6f3a07a05..de7e8c37af7f783668f6f50f0c25fa84ef6a87c0 100644
--- a/pkg/template_binding/test/template_binding_test.dart
+++ b/pkg/template_binding/test/template_binding_test.dart
@@ -397,6 +397,59 @@ templateInstantiationTests() {
     });
   });
 
+  test('Bind If minimal discardChanges', () {
+    var div = createTestHtml(
+        '<template bind="{{bound}}" if="{{predicate}}">value:{{ value }}'
+        '</template>');
+    // Dart Note: bound changed from null->{}.
+    var m = toObservable({ 'bound': {}, 'predicate': null });
+    var template = div.firstChild;
+
+    var discardChangesCalled = { 'bound': 0, 'predicate': 0 };
+    templateBind(template)
+        ..model = m
+        ..bindingDelegate =
+            new BindIfMinimalDiscardChanges(discardChangesCalled);
+
+    return new Future(() {
+      expect(discardChangesCalled['bound'], 0);
+      expect(discardChangesCalled['predicate'], 0);
+      expect(div.childNodes.length, 1);
+      m['predicate'] = 1;
+    }).then(endOfMicrotask).then((_) {
+      expect(discardChangesCalled['bound'], 1);
+      expect(discardChangesCalled['predicate'], 0);
+
+      expect(div.nodes.length, 2);
+      expect(div.lastChild.text, 'value:');
+
+      m['bound'] = toObservable({'value': 2});
+    }).then(endOfMicrotask).then((_) {
+      expect(discardChangesCalled['bound'], 1);
+      expect(discardChangesCalled['predicate'], 1);
+
+      expect(div.nodes.length, 2);
+      expect(div.lastChild.text, 'value:2');
+
+      m['bound']['value'] = 3;
+
+    }).then(endOfMicrotask).then((_) {
+      expect(discardChangesCalled['bound'], 1);
+      expect(discardChangesCalled['predicate'], 1);
+
+      expect(div.nodes.length, 2);
+      expect(div.lastChild.text, 'value:3');
+
+      templateBind(template).model = null;
+    }).then(endOfMicrotask).then((_) {
+      expect(discardChangesCalled['bound'], 1);
+      expect(discardChangesCalled['predicate'], 1);
+
+      expect(div.nodes.length, 1);
+    });
+  });
+
+
   test('Empty-If', () {
     var div = createTestHtml('<template if>{{ value }}</template>');
     var template = div.firstChild;
@@ -2643,6 +2696,29 @@ class Issue18Syntax extends BindingDelegate {
   }
 }
 
+class BindIfMinimalDiscardChanges extends BindingDelegate {
+  Map<String, int> discardChangesCalled;
+
+  BindIfMinimalDiscardChanges(this.discardChangesCalled) : super() {}
+
+  prepareBinding(path, name, node) {
+    return (model, node, oneTime) =>
+      new DiscardCountingPathObserver(discardChangesCalled, model, path);
+  }
+}
+
+class DiscardCountingPathObserver extends PathObserver {
+  Map<String, int> discardChangesCalled;
+
+  DiscardCountingPathObserver(this.discardChangesCalled, model, path)
+      : super(model, path) {}
+
+  get value {
+    discardChangesCalled[path.toString()]++;
+    return super.value;
+  }
+}
+
 class TestAccessorModel extends Observable {
   @observable var value = 1;
   var count = 0;