Platform.upgradeCustomElements for Dartium

tools/dom/src/dartium_Platform.dart

Index: tools/dom/src/dartium_Platform.dart
diff --git a/tools/dom/src/dartium_Platform.dart b/tools/dom/src/dartium_Platform.dart
index 48f323837dd3e2039e5f39265a8088a062454bef..34fdecced846032215b4712995dbfd2a21350526 100644
--- a/tools/dom/src/dartium_Platform.dart
+++ b/tools/dom/src/dartium_Platform.dart
@@ -24,8 +24,15 @@ class Platform {
    *
    * This is needed to cover timing scenarios which the custom element polyfill
    * does not cover.
+   *
+   * This is also a workaround for dartbug.com/12642 in Dartium.
    */
-  void upgradeCustomElements(Node node) {
+  static void upgradeCustomElements(Node node) {
     // no-op, provided for dart2js polyfill.
+    if (node is Element) {
+      (node as Element).queryAll('*');
+    } else {
+      node.nodes.forEach(upgradeCustomElements);
+    }
   }
 }