Options: Notify overlays that they will be closed if the options tab is closed.

chrome/browser/resources/options/options_page.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('options', function() {
   /////////////////////////////////////////////////////////////////////////////
   // OptionsPage class:
 
   /**
    * Base class for options page.
@@ skipping 442 matching lines @@
       if (this.isOverlayVisible_() &&
           !this.registeredOverlayPages[data.pageName.toLowerCase()]) {
         this.hideOverlay_();
       }
 
       this.showPageByName(data.pageName, false);
     }
   };
 
   /**
+   * Callback for window.onbeforeunload. Used to notify overlays that they will
+   * be closed.
+   */
+  OptionsPage.willClose = function() {
+    var overlay = this.getVisibleOverlay_();
+    if (overlay && overlay.didClosePage)
+      overlay.didClosePage();
+  };
+
+  /**
    * Freezes/unfreezes the scroll position of given level's page container.
    * @param {boolean} freeze Whether the page should be frozen.
    * @param {number} level The level to freeze/unfreeze.
    * @private
    */
   OptionsPage.setPageFrozenAtLevel_ = function(freeze, level) {
     var container = level == 0 ? $('toplevel-page-container')
                                : $('subpage-sheet-container-' + level);
 
     if (container.classList.contains('frozen') == freeze)
@@ skipping 516 matching lines @@
     shouldClose: function() {
       return true;
     },
   };
 
   // Export
   return {
     OptionsPage: OptionsPage
   };
 });