expose MDV addBindings

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 deb69d8182528e72a9b1347055fed7ac03a7de3c..42f8d389ab6daaf84730535076f2af80862dfa6e 100644
--- a/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLTemplateElement.darttemplate
@@ -86,6 +86,22 @@ $!MEMBERS
     _Bindings._bootstrapTemplatesRecursivelyFrom(content);
   }
 
+  /**
+   * Binds all mustaches recursively starting from the [root] node.
+   *
+   * Note: this is not an official Model-Driven-Views API; it is intended to
+   * support binding the [ShadowRoot]'s content to a model.
+   */
+  // TODO(jmesserly): this is needed to avoid two <template> nodes when using
+  // bindings in a custom element's template. See also:
+  // https://github.com/polymer-project/polymer/blob/master/src/bindMDV.js#L68
+  // Called from:
+  // https://github.com/polymer-project/polymer/blob/master/src/register.js#L99
+  @Experimental
+  static void bindModel(Node root, model, [CustomBindingSyntax syntax]) {
+    _Bindings._addBindings(root, model, syntax);
+  }
+
   static bool _initStyles;
 
   static void _injectStylesheet() {