Enables codegen support in polymer

pkg/polymer/lib/src/build/common.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.
 
 /// Common methods used by transfomers.
 library polymer.src.build.common;
 
 import 'dart:async';
 import 'dart:math' show min, max;
 
@@ skipping 170 matching lines @@
   var scanner = new Scanner(null, reader, errorListener);
   var token = scanner.tokenize();
   var parser = new Parser(null, errorListener);
   return parser.parseCompilationUnit(token);
 }
 
 class _ErrorCollector extends AnalysisErrorListener {
   final errors = <AnalysisError>[];
   onError(error) => errors.add(error);
 }
+
+/// These names have meaning in SVG or MathML, so they aren't allowed as custom
+/// tags. See [isCustomTagName].
+const invalidTagNames = const {
+  'annotation-xml': '',
+  'color-profile': '',
+  'font-face': '',
+  'font-face-src': '',
+  'font-face-uri': '',
+  'font-face-format': '',
+  'font-face-name': '',
+  'missing-glyph': '',
+};
+
+/// Returns true if this is a valid custom element name. See:
+/// <http://w3c.github.io/webcomponents/spec/custom/#dfn-custom-element-type>
+bool isCustomTagName(String name) {
+  if (name == null || !name.contains('-')) return false;
+  return !invalidTagNames.containsKey(name);
+}