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

tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate

Index: tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate b/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
index eb3eb5152169a2b27ea425b28f42d581d534b1e0..6a1bd4a0d0297848910db77e7b0f1d7c3e10ad9d 100644
--- a/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
@@ -6,7 +6,6 @@
 
 part of $LIBRARYNAME;
 
-
 /**
  * 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
@@ -15,32 +14,32 @@ part of $LIBRARYNAME;
  * 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.
+// 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.
 @Experimental()
-abstract class CustomBindingSyntax {
+abstract class BindingDelegate {
   /**
    * This syntax method allows for a custom interpretation of the contents of
    * mustaches (`{{` ... `}}`).
@@ -89,7 +88,6 @@ abstract class CustomBindingSyntax {
   getInstanceModel(Element template, model) => model;
 }
 
-
 @Experimental()
 $(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 $!MEMBERS
@@ -291,11 +289,4 @@ 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 = {};
 }