Add readonly check in Field.changed

src/model.js

@@ -1232,7 +1232,9 @@
         },
         changed: function(record) {
             var prms = [];
-            // TODO check readonly
+            if (this.get_state_attrs(record).readonly) {
+                return jQuery.when();
+            }
             prms.push(record.on_change([this.name]));
             prms.push(record.on_change_with([this.name]));
             prms.push(record.autocomplete_with(this.name));