Show parse errors in the UI when loading ONC files.

chrome/browser/resources/net_internals/chromeos_view.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * This view displays information on ChromeOS specific features.
  */
 var CrosView = (function() {
   'use strict';
 
   var fileContent;
   var passcode = '';
 
   /**
    *  Send file contents and passcode to C++ cros network library.
    *
    *  @private
    */
   function importONCFile_() {
     if (fileContent)
       g_browser.importONCFile(fileContent, passcode);
     else
-      setParseStatus_(false);
+      setParseStatus_('ONC file parse failed: cannot read file');
   }
 
   /**
    *  Set the passcode var, and trigger onc import.
    *
    *  @private
    *  @param {string} passcode
    */
   function setPasscode_(value) {
     passcode = value;
@@ skipping 28 matching lines @@
     } else {
       promptForPasscode_();
     }
   }
 
   /**
    *  Set ONC file parse status.
    *
    *  @private
    */
-  function setParseStatus_(success) {
+  function setParseStatus_(error) {
     var parseStatus = $(CrosView.PARSE_STATUS_ID);
     parseStatus.hidden = false;
-    parseStatus.textContent = success ?
-        "ONC file successfully parsed" : "ONC file parse failed";
+    parseStatus.textContent = error ?
+        'ONC file parse failed: ' + error : 'ONC file successfully parsed';
     reset_();
   }
 
   /**
    *  Add event listeners for the file selection and passcode input fields.
    *
    *  @private
    */
   function addEventListeners_() {
     $(CrosView.IMPORT_ONC_ID).addEventListener('change', function(event) {
@@ skipping 49 matching lines @@
 
   CrosView.prototype = {
     // Inherit from DivView.
     __proto__: DivView.prototype,
 
     onONCFileParse: setParseStatus_,
   };
 
   return CrosView;
 })();