Integrate About page into Settings for Chrome OS settings in a window.

ui/webui/resources/js/cr/ui/page_manager/page_manager.js

Index: ui/webui/resources/js/cr/ui/page_manager/page_manager.js
diff --git a/ui/webui/resources/js/cr/ui/page_manager/page_manager.js b/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
index 6f9f1cce3ffe6bd8bccb1c84cb3e3a46d359816e..e312b909f7aa0e0f11b76d6342289a4a4712c50a 100644
--- a/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
+++ b/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
@@ -193,7 +193,7 @@ cr.define('cr.ui.pageManager', function() {
                    this.registeredOverlayPages[name];
         if (!page.parentPage && isRootPageLocked)
           continue;
-        if (page.willHidePage && name != pageName &&
+        if (page.visible && name != pageName &&
             !this.isAncestorOfPage(page, targetPage)) {
           page.willHidePage();
         }
@@ -228,7 +228,7 @@ cr.define('cr.ui.pageManager', function() {
                    this.registeredOverlayPages[name];
         if (!page.parentPage && isRootPageLocked)
           continue;
-        if (!targetPageWasVisible && page.didShowPage &&
+        if (!targetPageWasVisible &&
             (name == pageName || this.isAncestorOfPage(page, targetPage))) {
           page.didShowPage();
         }
@@ -305,8 +305,9 @@ cr.define('cr.ui.pageManager', function() {
     onPageVisibilityChanged: function(page) {
       this.updateRootPageFreezeState();
 
-      for (var i = 0; i < this.observers_.length; ++i)
+      for (var i = 0; i < this.observers_.length; ++i) {
         this.observers_[i].onPageVisibilityChanged(page);
+      }
 
       if (!page.visible && this.isTopLevelOverlay(page))
         this.updateScrollPosition_();
@@ -332,9 +333,8 @@ cr.define('cr.ui.pageManager', function() {
         return;
 
       overlay.visible = false;
+      overlay.didClosePage();
 
-      if (overlay.didClosePage)
-        overlay.didClosePage();
       this.updateHistoryState_(false, {ignoreHash: true});
       this.updateTitle_();
 
@@ -420,7 +420,7 @@ cr.define('cr.ui.pageManager', function() {
                     this.defaultPage_;
       if (currentOverlay && !this.isAncestorOfPage(currentOverlay, newPage)) {
         currentOverlay.visible = false;
-        if (currentOverlay.didClosePage) currentOverlay.didClosePage();
+        currentOverlay.didClosePage();
       }
       this.showPageByName(pageName, false);
     },
@@ -440,7 +440,7 @@ cr.define('cr.ui.pageManager', function() {
      */
     willClose: function() {
       var overlay = this.getVisibleOverlay_();
-      if (overlay && overlay.didClosePage)
+      if (overlay)
         overlay.didClosePage();
     },
 
@@ -495,8 +495,7 @@ cr.define('cr.ui.pageManager', function() {
 
       if (!overlay.visible) {
         overlay.visible = true;
-        if (overlay.didShowPage)
-          overlay.didShowPage();
+        overlay.didShowPage();
       }
 
       // Change focus to the overlay if any other control was focused by