Generate EventListener attributes of non-EventTarget classes.

client/dom/generated/src/frog/FileWriter.dart

 
 class FileWriter native "*FileWriter" {
 
   static final int DONE = 2;
 
   static final int INIT = 0;
 
   static final int WRITING = 1;
 
   FileError error;
 
   int length;
 
+  EventListener onabort;
+
+  EventListener onerror;
+
+  EventListener onprogress;
+
+  EventListener onwrite;
+
+  EventListener onwriteend;
+
+  EventListener onwritestart;
+
   int position;
 
   int readyState;
 
   void abort() native;
 
   void seek(int position) native;
 
   void truncate(int size) native;
 
   void write(Blob data) native;
 
   var dartObjectLocalStorage;
 
   String get typeName() native;
 }