Fix static warnings in custom_element package

pkg/custom_element/lib/custom_element.dart

Index: pkg/custom_element/lib/custom_element.dart
diff --git a/pkg/custom_element/lib/custom_element.dart b/pkg/custom_element/lib/custom_element.dart
index 43366bce36e35834d06641ae7b4bf1ed6c0a82d1..9370cb364f6d040713adb4e6707c930efb61563a 100644
--- a/pkg/custom_element/lib/custom_element.dart
+++ b/pkg/custom_element/lib/custom_element.dart
@@ -304,12 +304,6 @@ class CustomElement implements Element {
 
   String get tagName => host.tagName;
 
-  String get pseudo => host.pseudo;
-
-  void set pseudo(String value) {
-    host.pseudo = value;
-  }
-
   // Note: we are not polyfilling the shadow root here. This will be fixed when
   // we migrate to the JS Shadow DOM polyfills. You can still use getShadowRoot
   // to retrieve a node that behaves as the shadow root when Shadow DOM is not
@@ -437,11 +431,7 @@ class CustomElement implements Element {
 
   void appendHtml(String html) => host.appendHtml(html);
 
-  String get regionOverset => host.regionOverset;
-
-  List<Range> getRegionFlowRanges() => host.getRegionFlowRanges();
-
-  void animate(List<Map> keyframes, [num duration]) =>
+  Animation animate(List<Map> keyframes, [num duration]) =>
       host.animate(keyframes, duration);
 
   // TODO(jmesserly): rename "created" to "onCreated".
@@ -481,6 +471,7 @@ class CustomElement implements Element {
   Stream<Event> get onFullscreenError => host.onFullscreenError;
   Stream<Event> get onPaste => host.onPaste;
   Stream<Event> get onReset => host.onReset;
+  Stream<Event> get onResize => host.onResize;
   Stream<Event> get onScroll => host.onScroll;
   Stream<Event> get onSearch => host.onSearch;
   Stream<Event> get onSelect => host.onSelect;