Print Preview: Hiding header/footer options when 'no margins' is selected

chrome/browser/resources/print_preview/header_footer_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 HeaderFooterSettings object. This object encapsulates all
    * settings and logic related to the headers and footers checkbox.
@@ skipping 26 matching lines @@
 
     /**
      * Adding listeners to header footer related controls.
      * @private
      */
     addEventListeners_: function() {
       this.headerFooterCheckbox_.onclick =
           this.onHeaderFooterChanged_.bind(this);
       document.addEventListener(customEvents.PDF_LOADED,
                                 this.onPDFLoaded_.bind(this));
+      document.addEventListener(customEvents.MARGINS_SELECTION_CHANGED,
+                                this.onMarginsSelectionChanged_.bind(this));
+    },
+
+    onMarginsSelectionChanged_: function(event) {
+      this.setVisible_(event.selectedMargins !=
+          print_preview.MarginSettings.MARGINS_VALUE_NO_MARGINS);
     },
 
     /**
      * Listener executing when the user selects or de-selects the headers
      * and footers option.
      * @private
      */
     onHeaderFooterChanged_: function() {
       requestPrintPreview();
     },
 
     /**
      * Listener executing when a |customEvents.PDF_LOADED| event occurs.
      * @private
      */
     onPDFLoaded_: function() {
-      if (!previewModifiable) {
+      if (!previewModifiable)
+        this.setVisible_(previewModifiable);
+    },
+
+    /**
+     * Hides or shows |this.headerFooterOption|.
+     * @{param} visible True if |this.headerFooterOption| should be shown.
+     * @private
+     */
+    setVisible_: function(visible) {
+      if (visible) {
+        fadeInOption(this.headerFooterOption_);
+      } else {
         fadeOutOption(this.headerFooterOption_);
         this.headerFooterCheckbox_.checked = false;

[dpapad, 2011/11/29 17:29:09]

When hiding this option we also set it to not checked, therefore
hasHeaderFooterEnabled returns false.

[kmadhusu, 2011/11/29 17:48:59]

Consider the following scenario:

1. User previews a document.
2. Selects "Default" in Margin settings.
3. Checks the header and footer option.
4. Selects "None" in Margin settings.

Code in line 84, unchecks the previous option selected by the user. When the
user selects "Default" again, the header and footer option is unchecked.


At this moment, we just need to hide the header and footer option but not change
the setting selected by the user. We should not uncheck the checkbox, instead
hasHeaderFooter() function needs to handle this case of identifying the current
margin settings and see if the header and footer is valid for that setting. 

[dpapad, 2011/11/29 19:32:07]

Done.

       }
     },
   };
 
   return {
     HeaderFooterSettings: HeaderFooterSettings,
   };
 });