Do not delete DOMStringMap and DOMStringList types from idl database.

lib/dom/src/native_DOMImplementation.dart

Index: lib/dom/src/native_DOMImplementation.dart
diff --git a/lib/dom/src/native_DOMImplementation.dart b/lib/dom/src/native_DOMImplementation.dart
index aa0a3ccca2aebd3ef3eef8d7bcc8f9f7e0b7c99f..cd652dc2c02bed0ba27f6e9b4a8e15fcadffc4f5 100644
--- a/lib/dom/src/native_DOMImplementation.dart
+++ b/lib/dom/src/native_DOMImplementation.dart
@@ -79,7 +79,7 @@ class LocationCrossFrameImplementation extends DOMWrapperBase implements Locatio
   String get typeName() => "Location";
 }
 
-class DOMStringMapImplementation extends DOMWrapperBase implements Map<String, String> {
+class DOMStringMapImplementation extends DOMWrapperBase implements DOMStringMap {
   static DOMStringMapImplementation _createDOMStringMapImplementation() => new DOMStringMapImplementation._createDOMStringMapImplementation();
   DOMStringMapImplementation._createDOMStringMapImplementation();
 
@@ -96,3 +96,10 @@ class DOMStringMapImplementation extends DOMWrapperBase implements Map<String, S
   int get length() => Maps.length(this);
   bool isEmpty() => Maps.isEmpty(this);
 }
+
+class DOMStringListImplementation extends DOMWrapperBase implements DOMStringList {
+  static DOMStringListImplementation _createDOMStringListImplementation() => new DOMStringListImplementation._createDOMStringListImplementation();
+  DOMStringListImplementation._createDOMStringListImplementation();
+
+  // FIXME: provide implementation.
+}