"Reverting 29728"

pkg/polymer_expressions/lib/polymer_expressions.dart

Index: pkg/polymer_expressions/lib/polymer_expressions.dart
diff --git a/pkg/polymer_expressions/lib/polymer_expressions.dart b/pkg/polymer_expressions/lib/polymer_expressions.dart
index 354fb5eb9958bf2100874438a16afe1e56b1ab63..0d4d06192fe05ad9292a8e0f768e7f5b427f2d3e 100644
--- a/pkg/polymer_expressions/lib/polymer_expressions.dart
+++ b/pkg/polymer_expressions/lib/polymer_expressions.dart
@@ -70,6 +70,17 @@ class PolymerExpressions extends BindingDelegate {
   prepareBinding(String path, name, node) {
     if (path == null) return null;
     var expr = new Parser(path).parse();
+
+    // For template bind/repeat to an empty path, just pass through the model.
+    // We don't want to unwrap the Scope.
+    // TODO(jmesserly): a custom element extending <template> could notice this
+    // behavior. An alternative is to associate the Scope with the node via an
+    // Expando, which is what the JavaScript PolymerExpressions does.
+    if (isSemanticTemplate(node) && (name == 'bind' || name == 'repeat') &&
+        expr is EmptyExpression) {
+      return null;
+    }
+
     return (model, node) {
       if (model is! Scope) {
         model = new Scope(model: model, variables: globals);