Add back invalid natives that couldn't be removed due to analyzer warnings.

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 aa78af799f0a0fca06244556fdc25f9fdc7fd320..b7ff13bc73efdb71a11fa26c4b2b5ac69936ffbc 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -32524,6 +32524,10 @@ class _SpeechInputResultList extends NativeFieldWrapperClass2 with ListMixin<Spe
   // To suppress missing implicit constructor warnings.
   factory _SpeechInputResultList._() { throw new UnsupportedError("Not supported"); }
 
+  @DomName('SpeechInputResultList.length')
+  @DocsEditable()
+  int get length => _blink.Native_SpeechInputResultList_length_Getter(this);
+
   SpeechInputResult operator[](int index) {
     if (index < 0 || index >= length)
       throw new RangeError.range(index, 0, length);