Show a different banner in chrome://settings for extension-controlled settings.

chrome/browser/resources/options/content_settings_ui.js

Index: chrome/browser/resources/options/content_settings_ui.js
diff --git a/chrome/browser/resources/options/content_settings_ui.js b/chrome/browser/resources/options/content_settings_ui.js
index fd61a0993c948dee787d02a219b356f9b3686219..d4c03bc05fbbe245bb61f4f502743fc26331b34e 100644
--- a/chrome/browser/resources/options/content_settings_ui.js
+++ b/chrome/browser/resources/options/content_settings_ui.js
@@ -27,6 +27,13 @@ cr.define('options', function() {
     },
   };
 
+  /**
+   * Whether the content setting is controlled by something else than the user's
+   * settings (either 'policy' or 'extension').
+   * @type {string}
+   */
+  cr.defineProperty(ContentSettingsRadio, 'controlledBy', cr.PropertyKind.ATTR);
+
   //////////////////////////////////////////////////////////////////////////////
   // HandlersEnabledRadio class: