Fix broken FileReader API in _blink_dartium

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 6f1430344e6dff9390313655005de9f4749b478f..79a166f408c23ebf7b5f51fcac1474ba4f0a2638 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -13020,6 +13020,10 @@ class FileReader extends EventTarget {
   @DocsEditable()
   int get readyState => _blink.BlinkFileReader.$readyState_Getter(this);
 
+  @DomName('FileReader.result')
+  @DocsEditable()
+  Object get _result => _blink.BlinkFileReader.$result_Getter(this);
+
   @DomName('FileReader.abort')
   @DocsEditable()
   void abort() => _blink.BlinkFileReader.$abort_Callback(this);