Support passing in handlers

Refs: #7621

@@ -111,6 +111,10 @@ define(function(require) {
                             self.model.set('prechecked', false);
                         }, 500);
                     });
+
+                    if (this.model.get('handlers') && this.model.get('handlers').uploadStart !== undefined) {
+                        this.model.get('handlers').uploadStart();
+                    }
                 }
             },
             fileAdded: function(flowFile) {
@@ -124,6 +128,10 @@ define(function(require) {
                     model.flowFile = flowFile;
                     this.model.get('collection').add(model);
                 }
+
+                if (this.model.get('handlers') && this.model.get('handlers').fileAdded !== undefined) {
+                    this.model.get('handlers').fileAdded(flowFile);
+                }
                 return true;
             },
             filesAdded: function() {