Fix for PDFs with lots of named destinations take a long time to load.

chrome/browser/resources/pdf/open_pdf_params_parser.js

 // Copyright 2014 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.
 
 'use strict';
 
 /**
  * Creates a new OpenPDFParamsParser. This parses the open pdf parameters
  * passed in the url to set initial viewport settings for opening the pdf.
  */
@@ skipping 34 matching lines @@
     viewportPosition['zoom'] = zoomFactor;
   },
 
   /**
    * @private
    * Parse PDF url parameters. These parameters are mentioned in the url
    * and specify actions to be performed when opening pdf files.
    * See http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/
    * pdfs/pdf_open_parameters.pdf for details.
    * @param {string} url that needs to be parsed.
+   * @param {Object} namedDestCallback Callback to be called to fetch page
+   * number for namedDestination.
+   * @param {boolean} isNavigate Tells weather this call happen for navigation
+   * as we need url for navigation case when we don't have page number for
+   * namedDestionation.
    * @return {Object} A dictionary containing the viewport which should be
    * displayed based on the URL.
    */
-  getViewportFromUrlParams: function(url) {
+  getViewportFromUrlParams: function(url, namedDestCallback, isNavigate) {

[raymes, 2015/02/12 22:19:05]

-None of the isNavigate stuff should be here, see the comment in the previous
file.
-This function should not return anything. The callback should always be called
with the viewport.
-we can just call namedDestCallback->callback

     var viewportPosition = {};
     var paramIndex = url.search('#');
     if (paramIndex == -1)
       return viewportPosition;

[raymes, 2015/02/12 22:19:05]

callback(viewportPosition)
return;

 
     var paramTokens = url.substring(paramIndex + 1).split('&');
     if ((paramTokens.length == 1) && (paramTokens[0].search('=') == -1)) {
       // Handle the case of http://foo.com/bar#NAMEDDEST. This is not
       // explicitlymentioned except by example in the Adobe
       // "PDF Open Parameters" document.
       viewportPosition['page'] = this.namedDestinations[paramTokens[0]];

[raymes, 2015/02/12 22:19:05]

This is where we need to call into the plugin. We should save off the state of
viewportPosition into a queue and call getNamedDestination:

this.outstandingRequests_.push({
  callback: callback,
  viewportPosition: viewportPosition
});
getNamedDestination(paramTokens[0]);
return;

And then in namedDestinationReceived:
namedDestinationReceived: function(namedDestinationPage) {
  var oustandingRequest = callback.shift();
  if (!outstandingRequest.viewportPosition.page)
    oustandingRequest.viewportPosition.page = namedDestinationPage;
  oustandingRequest.callback(oustandingRequest.viewportPosition);
}

+      if (viewportPosition['page'] == undefined) {
+        // -1 value indicates that we are going to get page number from plugin.
+        viewportPosition['page'] = -1;
+        if (isNavigate)
+          namedDestCallback(paramTokens[0], url);
+        else
+          namedDestCallback(paramTokens[0]);
+      }
       return viewportPosition;

[raymes, 2015/02/12 22:19:05]

callback(viewportPosition)
return;

     }
 
     var paramsDictionary = {};
     for (var i = 0; i < paramTokens.length; ++i) {
       var keyValueSplit = paramTokens[i].split('=');
       if (keyValueSplit.length != 2)
         continue;
       paramsDictionary[keyValueSplit[0]] = keyValueSplit[1];
     }
 
     if ('nameddest' in paramsDictionary) {
       var page = this.namedDestinations[paramsDictionary['nameddest']];
-      if (page != undefined)
+      if (page == undefined) {
+        // -1 value indicates that we are going to get page number from plugin.
+        viewportPosition['page'] = -1;
+        if (isNavigate)
+          namedDestCallback(paramsDictionary['nameddest'], url);
+        else
+          namedDestCallback(paramsDictionary['nameddest']);
+      } else {

[raymes, 2015/02/12 22:19:05]

The same thing here. We should shift this code this if-block right to the end of
the function and call:

this.outstandingRequests_.push({
  callback: callback,
  viewportPosition: viewportPosition
});
getNamedDestination(paramTokens[0]);
return;

         viewportPosition['page'] = page;
+      }
     }
 
     if ('page' in paramsDictionary) {
       // |pageNumber| is 1-based, but goToPage() take a zero-based page number.
       var pageNumber = parseInt(paramsDictionary['page']);
       if (!isNaN(pageNumber) && pageNumber > 0)
         viewportPosition['page'] = pageNumber - 1;
     }
 
     if ('zoom' in paramsDictionary)
       this.parseZoomParam_(paramsDictionary['zoom'], viewportPosition);
 
     return viewportPosition;

[raymes, 2015/02/12 22:19:05]

callback(viewportPosition)
return;

   }
 };