Updating Polymer to derive from custom elements.

pkg/polymer/lib/src/loader.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;
 
 /** Annotation used to automatically register polymer elements. */
 class CustomTag {
   final String tagName;
-  const CustomTag(this.tagName);
+  final Type type;
+  // TODO(13997): Remove the type parameter.
+  const CustomTag(this.tagName, {this.type});
 }
 
 /**
  * Metadata used to label static or top-level methods that are called
  * automatically when loading the library of a custom element.
  */
 const initMethod = const _InitMethodAnnotation();
 
 /**
  * Initializes a polymer application as follows:
  *   * set up up polling for observable changes
  *   *  initialize MDV
  *   *  for each library in [libraries], register custom elements labeled with
  *      [CustomTag] and invoke the initialization method on it.
  *
  * The initialization on each library is either a method named `main` or
  * a top-level function and annotated with [initMethod].
  *
  * The urls in [libraries] can be absolute or relative to [srcUrl].
  */
 void initPolymer(List<String> libraries, [String srcUrl]) {
   runMicrotask(() {
     // DOM events don't yet go through microtasks, so we catch those here.
     new Timer.periodic(new Duration(milliseconds: 125),
         (_) => performMicrotaskCheckpoint());
 
     // TODO(jmesserly): mdv should use initMdv instead of mdv.initialize.
     mdv.initialize();
-    registerCustomElement('polymer-element', () => new PolymerDeclaration());
+    document.register(PolymerDeclaration._TAG, PolymerDeclaration);
 
     for (var lib in libraries) {
       _loadLibrary(lib, srcUrl);
     }
 
     // TODO(jmesserly): this should be in the custom_element polyfill, not here.
     // notify the system that we are bootstrapped
     document.body.dispatchEvent(
         new CustomEvent('WebComponentsReady', canBubble: true));
   });
@@ skipping 33 matching lines @@
   // Search top-level functions marked with @initMethod
   for (var f in lib.functions.values) {
     _maybeInvoke(lib, f);
   }
 
   for (var c in lib.classes.values) {
     // Search for @CustomTag on classes
     for (var m in c.metadata) {
       var meta = m.reflectee;
       if (meta is CustomTag) {
-        Polymer._registerClassMirror(meta.tagName, c);
+        Polymer.register(meta.tagName, _getReflectedTypeWorkaround(c));
       }
     }
 
     // TODO(sigmund): check also static methods marked with @initMethod.
     // This is blocked on two bugs:
     //  - dartbug.com/12133 (static methods are incorrectly listed as top-level
     //    in dart2js, so they end up being called twice)
     //  - dartbug.com/12134 (sometimes "method.metadata" throws an exception,
     //    we could wrap and hide those exceptions, but it's not ideal).
   }
 }
 
+// Horrible hack to work around: http://dartbug.com/12607
+Type _getReflectedTypeWorkaround(ClassMirror cls) {
+  // On Dart VM, just return reflectedType.
+  if (1.0 is! int) return cls.reflectedType;
+
+  var mangledName = reflect(cls).getField(_mangledNameField).reflectee;
+  Type type = _jsHelper.invoke(#createRuntimeType, [mangledName]).reflectee;
+  return type;
+}
+
+final LibraryMirror _jsHelper =
+    currentMirrorSystem().libraries[Uri.parse('dart:_js_helper')];
+
+final Symbol _mangledNameField = () {
+  var jsClassMirrorMirror = reflect(reflectClass(ClassMirror)).type;
+  for (var name in jsClassMirrorMirror.variables.keys) {
+    if (MirrorSystem.getName(name) == '_mangledName') return name;
+  }
+}();
+
 void _maybeInvoke(ObjectMirror obj, MethodMirror method) {
   var annotationFound = false;
   for (var meta in method.metadata) {
     if (identical(meta.reflectee, initMethod)) {
       annotationFound = true;
       break;
     }
   }
   if (!annotationFound) return;
   if (!method.isStatic) {
     print("warning: methods marked with @initMethod should be static,"
         " ${method.simpleName} is not.");
     return;
   }
   if (!method.parameters.where((p) => !p.isOptional).isEmpty) {
     print("warning: methods marked with @initMethod should take no "
         "arguments, ${method.simpleName} expects some.");
     return;
   }
   obj.invoke(method.simpleName, const []);
 }
 
 class _InitMethodAnnotation {
   const _InitMethodAnnotation();
 }