A type for unsupported browser objects

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 b8ea186b852876abbddced28c4df78bccfc56430..b6e89158492d1a03a1eeb4249bab7f65d5ee6905 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -28752,10 +28752,10 @@ class Url extends NativeFieldWrapperClass2 implements UrlUtils {
     if ((blob_OR_source_OR_stream is Blob || blob_OR_source_OR_stream == null)) {
       return _blink.BlinkURL.$_createObjectURL_1_Callback(blob_OR_source_OR_stream);
     }
-    if ((blob_OR_source_OR_stream is MediaStream || blob_OR_source_OR_stream == null)) {
+    if ((blob_OR_source_OR_stream is MediaSource || blob_OR_source_OR_stream == null)) {
       return _blink.BlinkURL.$_createObjectURL_2_Callback(blob_OR_source_OR_stream);
     }
-    if ((blob_OR_source_OR_stream is MediaSource || blob_OR_source_OR_stream == null)) {
+    if ((blob_OR_source_OR_stream is MediaStream || blob_OR_source_OR_stream == null)) {
       return _blink.BlinkURL.$_createObjectURL_3_Callback(blob_OR_source_OR_stream);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -39021,3 +39021,7 @@ get _pureIsolateScheduleImmediateClosure => ((void callback()) =>
 void _initializeCustomElement(Element e) {
   _Utils.initializeCustomElement(e);
 }
+
+// Class for unsupported native browser 'DOM' objects.
+class _UnsupportedBrowserObject extends NativeFieldWrapperClass2 {
+}