Replace chrome::NOTIFICATION_EXTENSION_WARNING_CHANGED message with observer pattern

chrome/browser/ui/webui/extensions/extension_settings_handler.cc

Index: chrome/browser/ui/webui/extensions/extension_settings_handler.cc
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index 33ca78075ed79ce869356709179dc970837c3908..3bc35f8973fe725abeadc748e8a6aaa31c5bc731 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -21,7 +21,6 @@
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
-#include "chrome/browser/extensions/extension_warning_set.h"
 #include "chrome/browser/extensions/lazy_background_task_queue.h"
 #include "chrome/browser/extensions/unpacked_installer.h"
 #include "chrome/browser/extensions/updater/extension_updater.h"
@@ -86,6 +85,13 @@ ExtensionSettingsHandler::~ExtensionSettingsHandler() {
     load_extension_dialog_->ListenerDestroyed();
 
   registrar_.RemoveAll();
+
+  if (registered_for_notifications_) {
+    Profile* profile = Profile::FromWebUI(web_ui());
+    extensions::ExtensionWarningService* warnings =
+        extensions::ExtensionSystem::Get(profile)->warning_service();
+    warnings->RemoveObserver(this);
+  }
 }
 
 ExtensionSettingsHandler::ExtensionSettingsHandler(ExtensionService* service,
@@ -410,7 +416,6 @@ void ExtensionSettingsHandler::Observe(
     case chrome::NOTIFICATION_EXTENSION_LOADED:
     case chrome::NOTIFICATION_EXTENSION_UNLOADED:
     case chrome::NOTIFICATION_EXTENSION_UPDATE_DISABLED:
-    case chrome::NOTIFICATION_EXTENSION_WARNING_CHANGED:
     case chrome::NOTIFICATION_EXTENSION_BROWSER_ACTION_VISIBILITY_CHANGED:
     case chrome::NOTIFICATION_PREF_CHANGED:
       MaybeUpdateAfterNotification();
@@ -452,6 +457,10 @@ void ExtensionSettingsHandler::ExtensionUninstallCanceled() {
   extension_id_prompting_ = "";
 }
 
+void ExtensionSettingsHandler::ExtensionWarningsChanged() {
+  MaybeUpdateAfterNotification();
+}
+
 void ExtensionSettingsHandler::ReloadUnpackedExtensions() {
   const ExtensionSet* extensions = extension_service_->extensions();
   std::vector<const Extension*> unpacked_extensions;
@@ -782,8 +791,6 @@ void ExtensionSettingsHandler::MaybeRegisterForNotifications() {
                  content::Source<Profile>(profile));
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UPDATE_DISABLED,
                  content::Source<Profile>(profile));
-  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_WARNING_CHANGED,
-                 content::Source<Profile>(profile));
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_HOST_CREATED,
                  content::NotificationService::AllBrowserContextsAndSources());
   registrar_.Add(this,
@@ -804,6 +811,10 @@ void ExtensionSettingsHandler::MaybeRegisterForNotifications() {
       content::Source<extensions::ExtensionPrefs>(
           profile->GetExtensionService()->extension_prefs()));
 
+  extensions::ExtensionWarningService* warnings =
+      extensions::ExtensionSystem::Get(profile)->warning_service();
+  warnings->AddObserver(this);
+
   pref_registrar_.Init(profile->GetPrefs());
   pref_registrar_.Add(prefs::kExtensionInstallDenyList, this);
   local_state_pref_registrar_.Init(g_browser_process->local_state());