Use parseDirectives were possible. Also mark analyzer ready to be released.

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 'package:analyzer/src/generated/ast.dart';
@@ skipping 154 matching lines @@
       from: builder.join('/', builder.dirname(sourceId.path)));
 }
 
 
 /// Convert system paths to asset paths (asset paths are posix style).
 String _systemToAssetPath(String assetPath) {
   if (path.Style.platform != path.Style.windows) return assetPath;
   return path.posix.joinAll(path.split(assetPath));
 }
 
-
-/// Parse [code] using analyzer.
-CompilationUnit parseCompilationUnit(String code) {
-  var errorListener = new _ErrorCollector();
-  var reader = new CharSequenceReader(code);
-  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);
 }
 
 /// Regex to split names in the 'attributes' attribute, which supports 'a b c',
 /// 'a,b,c', or even 'a b,c'. This is the same as in `lib/src/declaration.dart`.
 final ATTRIBUTES_REGEX = new RegExp(r'\s|,');
 
 const POLYMER_EXPERIMENTAL_HTML = 'packages/polymer/polymer_experimental.html';