Animate TwoLevelList leading icon color

packages/flutter/lib/src/material/two_level_list.dart

@@ -7,6 +7,8 @@ import 'package:flutter/widgets.dart';
 import 'colors.dart';
 import 'icon.dart';
 import 'icons.dart';
+import 'icon_theme.dart';
+import 'icon_theme_data.dart';
 import 'list.dart';
 import 'list_item.dart';
 import 'theme.dart';
@@ -109,7 +111,9 @@ class _TwoLevelSublistState extends State<TwoLevelSublist> {
       ),
       child: new Column(
         children: <Widget>[
-          new TwoLevelListItem(
+          new IconTheme(
+            data: new IconThemeData(color: _iconColor.evaluate(_easeInAnimation)),
+            child: new TwoLevelListItem(
               onTap: _handleOnTap,
               leading: config.leading,
               title: new DefaultTextStyle(
@@ -119,8 +123,8 @@ class _TwoLevelSublistState extends State<TwoLevelSublist> {
               trailing: new RotationTransition(
                 turns: _iconTurns,
                 child: new Icon(
-                icon: Icons.expand_more,
-                color: _iconColor.evaluate(_easeInAnimation)
+                  icon: Icons.expand_more
+                )
               )
             )
           ),