"Reverting 28947"

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 48950cec8a4cddb4778a189df064e808fee6c76e..adc5b0e63c457ac6934ca8fb365dfcb3e65b0823 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -35204,6 +35204,16 @@ class Platform {
    * error.
    */
   static final supportsSimd = true;
+
+  /**
+   * Upgrade all custom elements in the subtree which have not been upgraded.
+   *
+   * This is needed to cover timing scenarios which the custom element polyfill
+   * does not cover.
+   */
+  static void upgradeCustomElements(Node node) {
+    // no-op, provided for dart2js polyfill.
+  }
 }
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
@@ -35326,8 +35336,6 @@ class _Utils {
 
   static bool isMap(obj) => obj is Map;
 
-  static List toListIfIterable(obj) => obj is Iterable ? obj.toList() : null;
-
   static Map createMap() => {};
 
   static makeUnimplementedError(String fileName, int lineNo) {
@@ -35634,6 +35642,10 @@ class _Utils {
 
   static bool isNoSuchMethodError(obj) => obj is NoSuchMethodError;
 
+  // TODO(jacobr): we need a failsafe way to determine that a Node is really a
+  // DOM node rather than just a class that extends Node.
+  static bool isNode(obj) => obj is Node;
+
   static bool _isBuiltinType(ClassMirror cls) {
     // TODO(vsm): Find a less hackish way to do this.
     LibraryMirror lib = cls.owner;