PrintPreview: Hide/Show the header footer option based on print frame margins.

chrome/browser/resources/print_preview/margin_settings.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.
 
 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 222 matching lines @@
           lastUsedMarginsType == MarginSettings.MARGINS_VALUE_CUSTOM;
       this.marginList_.selectedIndex =
           this.getMarginOptionIndexByValue_(lastUsedMarginsType);
       if (lastUsedMarginsSettings.hasOwnProperty('marginTop') &&
           lastUsedMarginsSettings.hasOwnProperty('marginBottom') &&
           lastUsedMarginsSettings.hasOwnProperty('marginRight') &&
           lastUsedMarginsSettings.hasOwnProperty('marginLeft')) {
         this.customMargins_ = new Margins(-1, -1, -1 , -1);
         this.customMargins = lastUsedMarginsSettings;
       }
-      this.dispatchMarginsChangedEvent_();
-    },
-
-    dispatchMarginsChangedEvent_: function() {
-      var customEvent = cr.Event(customEvents.MARGINS_SELECTION_CHANGED);
-      customEvent.selectedMargins = this.selectedMarginsValue;
-      document.dispatchEvent(customEvent);
     },
 
     /**
      * @return {number} The total width of the plugin in points.
      */
     get totalWidthInPoints() {
       var pageInformation = previewArea.pageLocationNormalized;
       return this.pageWidth_ / pageInformation.width;
     },
 
@@ skipping 300 matching lines @@
       this.forceDisplayingMarginLines_ = true;
       this.marginsUI.show();
     },
 
     /**
      * Executes when user selects a different margin option, ie,
      * |this.marginList_.selectedIndex| is changed.
      * @private
      */
     onMarginsChanged_: function() {
-      this.dispatchMarginsChangedEvent_();
-
       if (this.isDefaultMarginsSelected() || this.isMinimumMarginsSelected() ||
           this.isNoMarginsSelected())
         this.onDefaultMinimumNoMarginsSelected_();
       else if (this.isCustomMarginsSelected())
         this.onCustomMarginsSelected_();
     },
 
     /**
      * Executes when the default or minimum or no margins option is selected.
      * @private
@@ skipping 123 matching lines @@
       this.pageWidth_ = this.currentDefaultPageLayout.pageWidth;
       this.pageHeight_ = this.currentDefaultPageLayout.pageHeight;
     }
   };
 
   return {
     MarginSettings: MarginSettings,
     PageLayout: PageLayout
   };
 });