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

pkg/polymer/lib/src/instance.dart

Index: pkg/polymer/lib/src/instance.dart
diff --git a/pkg/polymer/lib/src/instance.dart b/pkg/polymer/lib/src/instance.dart
index e8777cebd5a8fd64896ef80c46b43d23fab5ff69..dc99d48e4a653db049634b5e123a44796d6a1e37 100644
--- a/pkg/polymer/lib/src/instance.dart
+++ b/pkg/polymer/lib/src/instance.dart
@@ -318,7 +318,7 @@ abstract class Polymer implements Element, Observable, NodeBindExtension {
   /** Locate nodes with id and store references to them in [$] hash. */
   void marshalNodeReferences(Node root) {
     if (root == null) return;
-    for (var n in (root as dynamic).queryAll('[id]')) {
+    for (var n in (root as dynamic).querySelectorAll('[id]')) {
       $[n.id] = n;
     }
   }