add @MirrorsUsed to observe/polymer/polymer_exprs pkgs

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);
@@ skipping 72 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.register(meta.tagName, _getReflectedTypeWorkaround(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();
 }