[Devtools] Fix to XMLView in Network Preview panel broken

third_party/WebKit/Source/devtools/front_end/network/RequestPreviewView.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 130 matching lines @@
      * @param {function(!WebInspector.Widget)} callback
      */
     _createPreviewView: function(callback)
     {
         if (this.request.contentError()) {
             callback(this._createMessageView(WebInspector.UIString("Failed to load response data")));
             return;
         }
 
         var xmlView = this._xmlView();
-        if (xmlView)
-            return xmlView;
+        if (xmlView) {
+            callback(xmlView);
+            return;
+        }
 
         WebInspector.JSONView.parseJSON(this._requestContent()).then(chooseView.bind(this)).then(callback);
 
         /**
          * @this {WebInspector.RequestPreviewView}
          * @param {?WebInspector.ParsedJSON} jsonData
          * @return {!WebInspector.Widget}
          */
         function chooseView(jsonData)
         {
@@ skipping 14 matching lines @@
 
             if (this.request.resourceType() === WebInspector.resourceTypes.Other)
                 return this._createEmptyWidget();
 
             return WebInspector.RequestView.nonSourceViewForRequest(this.request);
         }
     },
 
     __proto__: WebInspector.RequestContentView.prototype
 }