Settings Overides -- warn user when extensions override their NTP.

chrome/browser/ui/browser_tabstrip.cc

Index: chrome/browser/ui/browser_tabstrip.cc
diff --git a/chrome/browser/ui/browser_tabstrip.cc b/chrome/browser/ui/browser_tabstrip.cc
index 1018bbd2cb9d7df782a5bafc3b916ca6d51bd0fb..08c2f7f9cb92de63de22424f8214c23546a2ad02 100644
--- a/chrome/browser/ui/browser_tabstrip.cc
+++ b/chrome/browser/ui/browser_tabstrip.cc
@@ -16,6 +16,10 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 
+#if defined(TOOLKIT_VIEWS) && defined(OS_WIN)
+#include "chrome/browser/ui/views/settings_api_bubble_helper_views.h"
+#endif  // TOOLKIT_VIEWS && OS_WIN
+
 namespace chrome {
 
 void AddTabAt(Browser* browser, const GURL& url, int idx, bool foreground) {
@@ -32,6 +36,11 @@ void AddTabAt(Browser* browser, const GURL& url, int idx, bool foreground) {
   CoreTabHelper* core_tab_helper =
       CoreTabHelper::FromWebContents(params.target_contents);
   core_tab_helper->set_new_tab_start_time(new_tab_start_time);
+
+#if defined(TOOLKIT_VIEWS) && defined(OS_WIN)
+  if (url.is_empty())
+    extensions::MaybeShowExtensionControlledNewTabPage(browser);
+#endif
 }
 
 content::WebContents* AddSelectedTabWithURL(