Fix a crash in Chrome when clicking on the "Settings..." menu item for a desktop notification sho...

chrome/browser/ui/browser.cc

 // 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.
 
 #include "chrome/browser/ui/browser.h"
 
 #if defined(OS_WIN)
 #include <shellapi.h>
 #include <windows.h>
 #endif  // OS_WIN
@@ skipping 1972 matching lines @@
   std::string report_page_url =
       ReplaceStringPlaceholders(kBrokenPageUrl, subst, NULL);
   ShowSingletonTab(GURL(report_page_url));
 }
 
 void Browser::ShowOptionsTab(const std::string& sub_page) {
   browser::NavigateParams params(GetSingletonTabNavigateParams(
       GURL(chrome::kChromeUISettingsURL + sub_page)));
   params.path_behavior = browser::NavigateParams::IGNORE_AND_NAVIGATE;
 
-  if ((GetSelectedTabContents()->GetURL() == GURL(chrome::kChromeUINewTabURL) ||
+  if (GetSelectedTabContents() != NULL &&
+      (GetSelectedTabContents()->GetURL() == GURL(chrome::kChromeUINewTabURL) ||
        GetSelectedTabContents()->GetURL() == GURL(chrome::kAboutBlankURL)) &&
       browser::GetIndexOfSingletonTab(&params) < 0) {
     params.disposition = CURRENT_TAB;
   }
 
   browser::Navigate(&params);
 }
 
 void Browser::OpenClearBrowsingDataDialog() {
   UserMetrics::RecordAction(UserMetricsAction("ClearBrowsingData_ShowDlg"));
@@ skipping 2692 matching lines @@
   TabContents* current_tab = GetSelectedTabContents();
   if (current_tab) {
     content_restrictions = current_tab->content_restrictions();
     NavigationEntry* active_entry = current_tab->controller().GetActiveEntry();
     // See comment in UpdateCommandsForTabState about why we call url().
     if (!SavePackage::IsSavableURL(active_entry ? active_entry->url() : GURL()))
       content_restrictions |= CONTENT_RESTRICTION_SAVE;
   }
   return content_restrictions;
 }