Refactor the event-generation code to locate it in systemhtml.py.

client/html/generated/html/frog/DOMApplicationCache.dart

Index: client/html/generated/html/frog/DOMApplicationCache.dart
diff --git a/client/html/generated/html/frog/DOMApplicationCache.dart b/client/html/generated/html/frog/DOMApplicationCache.dart
index d450a089af54915eac55aec97a311f99b8559e31..c146c992541c786b533b11dc8369b6dadc9969d5 100644
--- a/client/html/generated/html/frog/DOMApplicationCache.dart
+++ b/client/html/generated/html/frog/DOMApplicationCache.dart
@@ -1,6 +1,9 @@
 
 class _DOMApplicationCacheImpl extends _EventTargetImpl implements DOMApplicationCache native "*DOMApplicationCache" {
 
+  _DOMApplicationCacheEventsImpl get on() =>
+    new _DOMApplicationCacheEventsImpl(this);
+
   static final int CHECKING = 2;
 
   static final int DOWNLOADING = 3;
@@ -15,9 +18,6 @@ class _DOMApplicationCacheImpl extends _EventTargetImpl implements DOMApplicatio
 
   final int status;
 
-  _DOMApplicationCacheEventsImpl get on() =>
-    new _DOMApplicationCacheEventsImpl(this);
-
   void abort() native;
 
   void _addEventListener(String type, EventListener listener, [bool useCapture = null]) native "this.addEventListener(type, listener, useCapture);";