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

pkg/polymer/test/event_handlers_test.dart

Index: pkg/polymer/test/event_handlers_test.dart
diff --git a/pkg/polymer/test/event_handlers_test.dart b/pkg/polymer/test/event_handlers_test.dart
index 33d8631c5031144a760e60b4985dcdb6b64d54d0..852d44d4812089057711bdde006a14fbcd9318be 100644
--- a/pkg/polymer/test/event_handlers_test.dart
+++ b/pkg/polymer/test/event_handlers_test.dart
@@ -114,7 +114,7 @@ main() {
 
   setUp(() => Polymer.onReady);
   test('events handled', () {
-    XTest test = query('x-test');
+    XTest test = querySelector('x-test');
     expect(test._onTestDone, isNotNull, reason: 'ready was called');
     return test._onTestDone;
   });