Set the attach file checkbox to checked when launched from an extension.

chrome/browser/resources/feedback.js

 // Copyright (c) 2012 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.
 
 // Constants.
 /** @const */ var FEEDBACK_LANDING_PAGE =
     'https://www.google.com/support/chrome/go/feedback_confirmation';
 /** @const */ var MAX_ATTACH_FILE_SIZE = 3 * 1024 * 1024;
 
 var selectedThumbnailDivId = '';
@@ skipping 287 matching lines @@
 
   // Set default values for the possible parameters, and then parse the actual
   // values from the URL href.
   var parameters = {
     'description': '',
     'categoryTag': '',
     'customPageUrl': '',
     'filePath': '',
   };
 
-  var query = window.location.search.substr(1).split('&');
+  var loc = window.location;
+  // Split the query string into an array of parameters.
+  var query = loc.search.substr(1).split('&');
+  // If we have a query in the hash.
+  if (loc.hash.indexOf('?') >= 0) {
+    // Remove the hash and split this query into parameters too.
+    query = query.concat(loc.hash.substr(loc.hash.indexOf('?') + 1).split('&'));
+  }
   for (var i = 0; i < query.length; i++) {
     // Decode and store each parameter value.
     parameter = query[i].split('=');
     parameters[parameter[0]] = decodeURIComponent(parameter[1]);
   }
 
   // Set the initial description text.
   $('description-text').textContent = parameters['description'];
   // If a page url is spcified in the parameters, override the default page url.
   if (parameters['customPageUrl'] != '') {
@@ skipping 77 matching lines @@
 
   if (!defaults.disableScreenshots)
     enableScreenshots();
 
   if (defaults.useSaved) {
     $('screenshot-link-tosaved').hidden = false;
   }
 }
 
 window.addEventListener('DOMContentLoaded', load);