Add constructors to all the event classes.

client/html/src/PopStateEvent.dart

Index: client/html/src/PopStateEvent.dart
diff --git a/client/html/generated/src/interface/PopStateEvent.dart b/client/html/src/PopStateEvent.dart
similarity index 57%
rename from client/html/generated/src/interface/PopStateEvent.dart
rename to client/html/src/PopStateEvent.dart
index 5ea430f010d5bbb4402ae41b8ff2bbcbf8f299ae..c1392b154aa8306a385c783b4c8263c81a1802da 100644
--- a/client/html/generated/src/interface/PopStateEvent.dart
+++ b/client/html/src/PopStateEvent.dart
@@ -2,11 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// WARNING: Do not edit - generated code.
+interface PopStateEvent extends Event factory PopStateEventWrappingImplementation {
 
-interface PopStateEvent extends Event {
+  PopStateEvent(String type, Object state, [bool canBubble, bool cancelable]);
 
   String get state();
-
-  void initPopStateEvent(String typeArg, bool canBubbleArg, bool cancelableArg, Object stateArg);
 }