unittest step2: bye bye to multiple entrypoints for unittest

client/tests/client/dom/CallbacksTest.dart

Index: client/tests/client/dom/CallbacksTest.dart
diff --git a/client/tests/client/dom/CallbacksTest.dart b/client/tests/client/dom/CallbacksTest.dart
index e2f6bde5991c5eaf1f3eeac0d3b388f8436e6fb3..237e6e961954cea252d3b44a6ac369ccff0ffe76 100644
--- a/client/tests/client/dom/CallbacksTest.dart
+++ b/client/tests/client/dom/CallbacksTest.dart
@@ -1,9 +1,10 @@
 #library('CallbacksTest');
-#import('../../../../lib/unittest/unittest_dom.dart');
+#import('../../../../lib/unittest/unittest.dart');
+#import('../../../../lib/unittest/dom_config.dart');
 #import('dart:dom');
 
 main() {
-  forLayoutTests();
+  useDomConfiguration(isLayoutTest: true);
   test('RequestAnimationFrameCallback', () {
     window.webkitRequestAnimationFrame((int time) => false);
   });