Fix some users of removed mirror API.

pkg/polymer/lib/src/declaration.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;
 
 /**
  * **Warning**: this class is experiental and subject to change.
  *
  * The implementation for the `polymer-element` element.
@@ skipping 204 matching lines @@
     // Potentially remove when spec bug is addressed.
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=21407
     // TODO(jmesserly): resolvePath not ported, see first comment in this class.
 
     // under ShadowDOMPolyfill, transforms to approximate missing CSS features
     _shimShadowDomStyling(templateContent, name, extendee);
 
     var cls = reflectClass(type);
     // TODO(jmesserly): this feels unnatrual in Dart. Since we have convenient
     // lazy static initialization, can we get by without it?
-    var registered = cls.methods[#registerCallback];
-    if (registered != null && registered.isStatic &&
+    var registered = cls.declarations[#registerCallback];
+    if (registered != null &&
+        registered is MethodMirror &&
+        registered.isStatic &&
         registered.isRegularMethod) {
       cls.invoke(#registerCallback, [this]);
     }
   }
 
   void registerType(String name) {
     var baseTag;
     var decl = this;
     while (decl != null) {
       baseTag = decl.attributes['extends'];
@@ skipping 372 matching lines @@
   return map;
 }();
 
 // Dart note: we need this function because we have additional renames JS does
 // not have. The JS renames are simply case differences, whereas we have ones
 // like doubleclick -> dblclick and stripping the webkit prefix.
 String _eventNameFromType(String eventType) {
   final result = _reverseEventTranslations[eventType];
   return result != null ? result : eventType;
 }