Print Preview: Fixing javascript error occuring in the margins code.

chrome/browser/resources/print_preview/margin_settings.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.
 
 cr.define('print_preview', function() {
   'use strict';
 
   /**
    * Creates a Margins object that holds four margin values. The units in which
    * the values are expressed can be any numeric value.
@@ skipping 517 matching lines @@
                             this.getMarginValueLimits_(),
                             keepDisplayedValue,
                             this.getMarginValueLimitsInPercent_());
       this.marginsUI.draw();
     },
 
     /**
      * Called when there is change in the preview position or size.
      */
     onPreviewPositionChanged: function() {
+      if (!previewArea.pdfPlugin)
+        return;
       if (this.isCustomMarginsSelected() && previewArea.pdfLoaded &&
           pageSettings.totalPageCount != undefined) {
+        this.updatePageData_();

[kmadhusu, 2011/11/21 19:20:22]

Can you explain why you need to update the page data here?

[dpapad, 2011/11/22 02:05:10]

Yes. cutomMargins_ might not be initialized when this code executes (because of
the checks added in line 586 which are necessary). Therefore they need to be
initialized here before drawing the lines.

         this.drawCustomMarginsUI_();
       }
     },
 
     /**
      * Executes when a margin textbox is focused. Used for improved
      * accessibility.
      * @private
      */
     onMarginTextboxFocused_: function() {
@@ skipping 23 matching lines @@
       this.forceDisplayingMarginLines_ = true;
       this.previousCustomMargins_ = null;
       setDefaultValuesAndRegeneratePreview(false);
     },
 
     /**
      * Executes when the custom margins option is selected.
      * @private
      */
     onCustomMarginsSelected_: function() {
+      if (!previewArea.pdfPlugin) {
+        this.forceMarginsUIOnPDFLoad_ = true;
+        return;
+      }
       var customMarginsNotSpecified = !this.customMargins_;
       this.updatePageData_();
 
       if (customMarginsNotSpecified) {
         this.previousCustomMargins_ = this.customMargins_.clone();
         this.drawCustomMarginsUI_();
         this.addCustomMarginEventListeners_();
         this.marginsUI.show();
       } else {
         this.forceMarginsUIOnPDFLoad_ = true;
@@ skipping 96 matching lines @@
       this.pageWidth_ = this.currentDefaultPageLayout.pageWidth;
       this.pageHeight_ = this.currentDefaultPageLayout.pageHeight;
     }
   };
 
   return {
     MarginSettings: MarginSettings,
     PageLayout: PageLayout,
   };
 });