Fix the System Profile to not load extensions. It could otherwise be forced to by GPO.

chrome/browser/extensions/chrome_process_manager_delegate.cc

Index: chrome/browser/extensions/chrome_process_manager_delegate.cc
diff --git a/chrome/browser/extensions/chrome_process_manager_delegate.cc b/chrome/browser/extensions/chrome_process_manager_delegate.cc
index e3d1354a1b64bea5bb82e2dba383178f22811dec..d141058e816c738f36a8af8d3c4b5b28bf3efc03 100644
--- a/chrome/browser/extensions/chrome_process_manager_delegate.cc
+++ b/chrome/browser/extensions/chrome_process_manager_delegate.cc
@@ -41,7 +41,8 @@ bool ChromeProcessManagerDelegate::IsBackgroundPageAllowed(
     content::BrowserContext* context) const {
   Profile* profile = static_cast<Profile*>(context);
 
-  bool is_normal_session = !profile->IsGuestSession();
+  bool is_normal_session = !profile->IsGuestSession() &&
+                           !profile->IsSystemProfile();
 #if defined(OS_CHROMEOS)
   is_normal_session = is_normal_session &&
                       user_manager::UserManager::Get()->IsUserLoggedIn();