Removed polymer from dart2js transformer

TBR=johnmccutchan@google.com

Review URL: https://codereview.chromium.org//2318373002 .
diff --git a/pubspec.yaml b/pubspec.yaml
index 5fbb150..d33b211 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -3,7 +3,6 @@
 transformers:
 - dart_to_js_script_rewriter
 - $dart2js:
-    $include: "**/*.polymer.bootstrap.dart"
     suppressWarnings: false
     commandLineOptions: [--show-package-warnings]
 dependencies: