Untested hacks to swarm to avoid warnings.

samples-dev/swarm/UIState.dart

Index: samples-dev/swarm/UIState.dart
diff --git a/samples-dev/swarm/UIState.dart b/samples-dev/swarm/UIState.dart
index dffb1c799e69bf6c7c7866b1e2f93003380e24e7..2d408431b493abc03bc108c478a1215260cffc77 100644
--- a/samples-dev/swarm/UIState.dart
+++ b/samples-dev/swarm/UIState.dart
@@ -60,7 +60,8 @@ abstract class UIState {
     // TODO(jmesserly): [state] should be an Object, and we should pass it to
     // the state parameter instead of as a #hash URL. Right now we're working
     //  around b/4582542.
-    window.history.pushState(null, '${document.title}#$state');
+    window.history.pushState(null,
+        '${document.title}', '${document.title}#$state');
   }
 
   /**