[polymer] fix editor hints -- query/queryAll and unused imports

pkg/polymer/test/publish_attributes_test.dart

Index: pkg/polymer/test/publish_attributes_test.dart
diff --git a/pkg/polymer/test/publish_attributes_test.dart b/pkg/polymer/test/publish_attributes_test.dart
index 78bd593d78bd542a4348793592ee06599ffc231d..6ff61a89662f493f5967ad0ff8a015b9d9dd2790 100644
--- a/pkg/polymer/test/publish_attributes_test.dart
+++ b/pkg/polymer/test/publish_attributes_test.dart
@@ -59,7 +59,7 @@ main() {
   setUp(() => Polymer.onReady);
 
   test('published properties', () {
-    published(tag) => (query('polymer-element[name=$tag]')
+    published(tag) => (querySelector('polymer-element[name=$tag]')
         as PolymerDeclaration).publishedProperties;
 
     expect(published('x-foo'), ['Foo', 'baz']);