2nd try: SDK dep cleanup

tests/html/utils.dart

 library TestUtils;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:js' as js;
 import 'dart:typed_data';
 import 'package:unittest/unittest.dart';
-export 'package:web_components/polyfill.dart';
 
 /**
  * Verifies that [actual] has the same graph structure as [expected].
  * Detects cycles and DAG structure in Maps and Lists.
  */
 verifyGraph(expected, actual) {
   var eItems = [];
   var aItems = [];
 
   message(path, reason) => path == ''
@@ skipping 141 matching lines @@
  *
  * This is needed to cover timing scenarios which the custom element polyfill
  * does not cover.
  */
 void upgradeCustomElements(Node node) {
   if (js.context.hasProperty('CustomElements') &&
       js.context['CustomElements'].hasProperty('upgradeAll')) {
     js.context['CustomElements'].callMethod('upgradeAll', [node]);
   }
 }
+

[devoncarew, 2017/07/18 19:54:44]

Is this the same code you're also adding to `tests/lib_strong/html/utils.dart`?
Can we share it?

+/**
+ * A future that completes once all custom elements in the initial HTML page
+ * have been upgraded.
+ *
+ * This is needed because the native implementation can update the elements
+ * while parsing the HTML document, but the custom element polyfill cannot,
+ * so it completes this future once all elements are upgraded.
+ */
+// TODO(jmesserly): rename to webComponentsReady to match the event?
+Future customElementsReady = () {
+  if (_isReady) return new Future.value();
+
+  // Not upgraded. Wait for the polyfill to fire the WebComponentsReady event.
+  // Note: we listen on document (not on document.body) to allow this polyfill
+  // to be loaded in the HEAD element.
+  return document.on['WebComponentsReady'].first;
+}();
+
+// Return true if we are using the polyfill and upgrade is complete, or if we
+// have native document.register and therefore the browser took care of it.
+// Otherwise return false, including the case where we can't find the polyfill.
+bool get _isReady {
+  // If we don't have dart:js, assume things are ready
+  if (js.context == null) return true;
+
+  var customElements = js.context['CustomElements'];
+  if (customElements == null) {
+    // Return true if native document.register, otherwise false.
+    // (Maybe the polyfill isn't loaded yet. Wait for it.)
+    return document.supportsRegisterElement;
+  }
+
+  return customElements['ready'] == true;
+}
+
+/**
+ * *Note* this API is primarily intended for tests. In other code it is better
+ * to write it in a style that works with or without the polyfill, rather than
+ * using this method.
+ *
+ * Synchronously trigger evaluation of pending lifecycle events, which otherwise
+ * need to wait for a [MutationObserver] to signal the changes in the polyfill.
+ * This method can be used to resolve differences in timing between native and
+ * polyfilled custom elements.
+ */
+void customElementsTakeRecords([Node node]) {
+  var customElements = js.context['CustomElements'];
+  if (customElements == null) return;
+  customElements.callMethod('takeRecords', [node]);
+}