remove code-transformers from the repo

pkg/code_transformers/lib/src/messages.dart

Index: pkg/code_transformers/lib/src/messages.dart
diff --git a/pkg/code_transformers/lib/src/messages.dart b/pkg/code_transformers/lib/src/messages.dart
deleted file mode 100644
index a1a8e58019244d6a3f18978bcd793c96abb66c21..0000000000000000000000000000000000000000
--- a/pkg/code_transformers/lib/src/messages.dart
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright (c) 2014, 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.
-
-/// Contains all warning messages produced by the code_transformers package.
-library code_transformers.src.messages;
-
-import 'package:code_transformers/messages/messages.dart';
-
-const NO_ABSOLUTE_PATHS = const MessageTemplate(
-    const MessageId('code_transformers', 1),
-    'absolute paths not allowed: "%-url-%"',
-    'Absolute paths not allowed',
-    '''
-The transformers processing your code were trying to resolve a URL and identify
-a file that they correspond to. Currently only relative paths can be resolved.
-''');
-
-const INVALID_URL_TO_OTHER_PACKAGE = const MessageTemplate(
-    const MessageId('code_transformers', 2),
-    'Invalid URL to reach to another package: %-url-%. Path '
-    'reaching to other packages must first reach up all the '
-    'way to the %-prefix-% directory. For example, try changing the URL '
-    'to: %-fixedUrl-%',
-    'Invalid URL to reach another package',
-    '''
-To reach an asset that belongs to another package, use `package:` URLs in
-Dart code, but in any other language (like HTML or CSS) use relative URLs that
-first go all the way to the `packages/` directory.
-
-The rules for correctly writing these imports are subtle and have a lot of
-special cases. Please review
-<https://www.dartlang.org/polymer/app-directories.html> to learn
-more.
-''');
-
-const INVALID_PREFIX_PATH = const MessageTemplate(
-    const MessageId('code_transformers', 3),
-    'incomplete %-prefix-%/ path. It should have at least 3 '
-    'segments %-prefix-%/name/path_from_name\'s_%-folder-%_dir',
-    'Incomplete URL to asset in another package',
-    '''
-URLs that refer to assets in other packages need to explicitly mention the
-`packages/` directory. In the future this requirement might be removed, but for
-now you must use a canonical URL form for it.
-
-For example, if `packages/a/a.html` needs to import `packages/b/b.html`,
-you might expect a.html to import `../b/b.html`. Instead, it must import
-`../../packages/b/b.html`.
-
-See [issue 15797](http://dartbug.com/15797) and
-<https://www.dartlang.org/polymer/app-directories.html> to learn more.
-''');