remove new

lib/material/images.dart

@@ -48,7 +48,7 @@ class IconDragon extends StatefulWidget {
 
   @override
   _IconDragonState createState() {
-    return new _IconDragonState();
+    return _IconDragonState();
   }
 }
 

lib/panel/controller.dart

@@ -236,7 +236,7 @@ class _Button extends StatefulWidget {
 
   @override
   _ButtonState createState() {
-    return new _ButtonState();
+    return _ButtonState();
   }
 }
 

lib/panel/status_panel.dart

@@ -67,7 +67,7 @@ class _NextBlock extends StatelessWidget {
 class _GameStatus extends StatefulWidget {
   @override
   _GameStatusState createState() {
-    return new _GameStatusState();
+    return _GameStatusState();
   }
 }