[polymer] add a new API to create an element without polymer-element in HTML

pkg/polymer/lib/src/instance.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of polymer;
 
 /// Use this annotation to publish a field as an attribute. For example:
 ///
 ///     class MyPlaybackElement extends PolymerElement {
 ///       // This will be available as an HTML attribute, for example:
@@ skipping 61 matching lines @@
     if (type == null) type = PolymerElement;
 
     _typesByName[name] = type;
 
     // Dart note: here we notify JS of the element registration. We don't pass
     // the Dart type because we will handle that in PolymerDeclaration.
     // See _hookJsPolymerDeclaration for how this is done.
     (js.context['Polymer'] as JsFunction).apply([name]);
   }
 
+  /// Register a custom element that has no associated `<polymer-element>`.
+  /// Unlike [register] this will always perform synchronous registration and
+  /// by the time this method returns the element will be available using
+  /// [document.createElement] or by modifying the HTML to include the element.
+  static void registerSync(String name, Type type,
+      {String extendsTag, Document doc, Node template}) {
+
+    // Our normal registration, this will queue up the name->type association.
+    register(name, type);
+
+    // Build a polymer-element and initialize it to register
+    if (doc == null) doc = document;
+    var poly = doc.createElement('polymer-element');
+    poly.attributes['name'] = name;
+    if (extendsTag != null) poly.attributes['extends'] = extendsTag;
+    if (template != null) poly.append(template);
+
+    new JsObject.fromBrowserObject(poly).callMethod('init');
+  }
+
   /// The one syntax to rule them all.
   static final BindingDelegate _polymerSyntax =
       new PolymerExpressionsWithEvents();
 
   static int _preparingElements = 0;
 
   static final Completer _ready = new Completer();
 
   /// Future indicating that the Polymer library has been loaded and is ready
   /// for use.
@@ skipping 929 matching lines @@
     if (_sub != null) {
       if (_eventsLog.isLoggable(Level.FINE)) {
         _eventsLog.fine(
             'event.remove: [$_node].$_eventName => [$_model].$_path())');
       }
      _sub.cancel();
       _sub = null;
     }
   }
 }