Custom Syntax's are now enabled via template.bindingDelegate =

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 2870931c48a5e8e8b2d82acc62f5573727bfa9d1..887b4dc2ada4263a1a17c3edad9ecc8025e1c9dc 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -8614,13 +8614,15 @@ abstract class Element extends Node implements ElementTraversal native "Element"
   }
 
   /**
-   * Creates an instance of the template.
+   * Creates an instance of the template, using the provided model and binding
+   * delegate.
+   *
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
-  DocumentFragment createInstance(model, String syntax) {
+  DocumentFragment createInstance(model, BindingDelegate delegate) {
     _ensureTemplate();
-    return TemplateElement.mdvPackage(this).createInstance(model, syntax);
+    return TemplateElement.mdvPackage(this).createInstance(model, delegate);
   }
 
   /**
@@ -8636,6 +8638,22 @@ abstract class Element extends Node implements ElementTraversal native "Element"
     TemplateElement.mdvPackage(this).model = value;
   }
 
+  /**
+   * The binding delegate which is inherited through the tree. It can be used
+   * to configure custom syntax for `{{bindings}}` inside this template.
+   *
+   * This is only supported if [isTemplate] is true.
+   */
+  @Experimental()
+  BindingDelegate get bindingDelegate =>
+      TemplateElement.mdvPackage(this).bindingDelegate;
+
+  @Experimental()
+  void set bindingDelegate(BindingDelegate value) {
+    _ensureTemplate();
+    TemplateElement.mdvPackage(this).bindingDelegate = value;
+  }
+
   // TODO(jmesserly): const set would be better
   static const _TABLE_TAGS = const {
     'caption': null,
@@ -21393,7 +21411,6 @@ class TableSectionElement extends _HTMLElement native "HTMLTableSectionElement"
 // WARNING: Do not edit - generated code.
 
 
-
 /**
  * Model-Driven Views (MDV)'s native features enables a wide-range of use cases,
  * but (by design) don't attempt to implement a wide array of specialized
@@ -21402,32 +21419,31 @@ class TableSectionElement extends _HTMLElement native "HTMLTableSectionElement"
  * Enabling these features in MDV is a matter of implementing and registering an
  * MDV Custom Syntax. A Custom Syntax is an object which contains one or more
  * delegation functions which implement specialized behavior. This object is
- * registered with MDV via [TemplateElement.syntax]:
+ * registered with MDV via [Element.bindingDelegate]:
  *
  *
  * HTML:
- *     <template bind syntax="MySyntax">
+ *     <template bind>
  *       {{ What!Ever('crazy')->thing^^^I+Want(data) }}
  *     </template>
  *
  * Dart:
- *     class MySyntax extends CustomBindingSyntax {
+ *     class MySyntax extends BindingDelegate {
  *       getBinding(model, path, name, node) {
  *         // The magic happens here!
  *       }
  *     }
- *
  *     ...
- *
- *     TemplateElement.syntax['MySyntax'] = new MySyntax();
+ *     query('template').bindingDelegate = new MySyntax();
+ *     query('template').model = new MyModel();
  *
  * See <https://github.com/polymer-project/mdv/blob/master/docs/syntax.md> for
  * more information about Custom Syntax.
  */
-// TODO(jmesserly): if this is just one method, a function type would make it
-// more Dart-friendly.
-@Experimental()
-abstract class CustomBindingSyntax {
+// TODO(jmesserly): move this type to the MDV package? Two issues: we'd lose
+// type annotation on [Element.bindingDelegate], and "mdv" is normally imported
+// with a prefix.
+abstract class BindingDelegate {
   /**
    * This syntax method allows for a custom interpretation of the contents of
    * mustaches (`{{` ... `}}`).
@@ -21476,7 +21492,6 @@ abstract class CustomBindingSyntax {
   getInstanceModel(Element template, model) => model;
 }
 
-
 @Experimental()
 @DomName('HTMLTemplateElement')
 @SupportedBrowser(SupportedBrowser.CHROME)
@@ -21696,13 +21711,6 @@ option[template] {
 }''';
     document.head.append(style);
   }
-
-  /**
-   * A mapping of names to Custom Syntax objects. See [CustomBindingSyntax] for
-   * more information.
-   */
-  @Experimental()
-  static Map<String, CustomBindingSyntax> syntax = {};
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a