Refactoring two pieces of polymer:

pkg/polymer/lib/polymer.dart

 // Copyright (c) 2012, 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.
 
 /// Custom HTML tags, data binding, and templates for building
 /// structured, encapsulated, client-side web apps.
 ///
 /// Polymer.dart, the next evolution of Web UI,
 /// is an in-progress Dart port of the
 /// [Polymer project](http://www.polymer-project.org/).
@@ skipping 31 matching lines @@
 // TODO(jmesserly): we need to do a redundancy check. Some code like the FOUC
 // protection seems out of date, as if left over from the older
 // b7200854b2441a22ce89f6563963f36c50f5150d baseline.
 
 import 'dart:async';
 import 'dart:collection' show HashMap, HashSet, LinkedHashMap;
 import 'dart:html';
 import 'dart:js' as js show context;
 import 'dart:js' hide context;
 
+// *** Important Note ***
+// This import is automatically replaced when calling pub build by the
+// mirrors_remover transformer. The transformer will remove any dependencies on
+// dart:mirrors in deployed polymer apps. This and the import to
+// mirror_loader.dart below should be updated in sync with changed in
+// lib/src/build/mirrors_remover.dart.
+//
+// Technically, if we have codegen for expressions we shouldn't need any
+// @MirrorsUsed (since this is for development only), but our test bots don't
+// run pub-build yet. Until then, polymer might be tested with mirror_loader
+// instead of the static_loader, however the actual code there is practically
+// dead ([initializers] will be set programatically with generated code
+// anyways), but the @MirrorsUsed helps reduce the load on our bots.
 @MirrorsUsed(metaTargets:
-    const [Reflectable, ObservableProperty, PublishedProperty, CustomTag,
-        _InitMethodAnnotation],
+    const [Reflectable, ObservableProperty, PublishedProperty, CustomTag],
     targets: const [PublishedProperty],
-    override: const ['smoke.mirrors', 'polymer'])
-import 'dart:mirrors';
+    override: const ['smoke.mirrors'])
+import 'dart:mirrors' show MirrorsUsed;    // ** see important note above
 
 import 'package:logging/logging.dart' show Logger, Level;
 import 'package:observe/observe.dart';
 import 'package:observe/src/dirty_check.dart' show dirtyCheckZone;
 import 'package:path/path.dart' as path;
 import 'package:polymer_expressions/polymer_expressions.dart'
     show PolymerExpressions;
 import 'package:smoke/smoke.dart' as smoke;
 import 'package:smoke/mirrors.dart' as smoke;
 import 'package:template_binding/template_binding.dart';
 import 'package:web_components/polyfill.dart' show customElementsReady;
 
 import 'deserialize.dart' as deserialize;
+import 'src/mirror_loader.dart' as loader; // ** see important note above
 
 export 'package:observe/observe.dart';
 export 'package:observe/html.dart';
 
 part 'src/declaration.dart';
 part 'src/instance.dart';
 part 'src/job.dart';
 part 'src/loader.dart';