[Extensions] Remove the prompt to re-enable app when visiting its site

chrome/browser/extensions/extension_system_impl.h

Index: chrome/browser/extensions/extension_system_impl.h
diff --git a/chrome/browser/extensions/extension_system_impl.h b/chrome/browser/extensions/extension_system_impl.h
index 03a6c890a8b175a07277e481c72066c4696ed85f..e6cd8da42fcc6cb5baa1bf30572beebebdd13a59 100644
--- a/chrome/browser/extensions/extension_system_impl.h
+++ b/chrome/browser/extensions/extension_system_impl.h
@@ -24,7 +24,6 @@ class SigninScreenPolicyProvider;
 namespace extensions {
 
 class ExtensionSystemSharedFactory;
-class NavigationObserver;
 class StateStoreNotificationObserver;
 class UninstallPingSender;
 class InstallGate;
@@ -117,7 +116,6 @@ class ExtensionSystemImpl : public ExtensionSystem {
         state_store_notification_observer_;
     std::unique_ptr<StateStore> rules_store_;
     scoped_refptr<ValueStoreFactoryImpl> store_factory_;
-    std::unique_ptr<NavigationObserver> navigation_observer_;
     std::unique_ptr<ServiceWorkerManager> service_worker_manager_;
     // Shared memory region manager for scripts statically declared in extension
     // manifests. This region is shared between all extensions.