[Do not commit] Track revocations in content_settings::Observer

chrome/browser/ui/webui/options/content_settings_handler.cc

Index: chrome/browser/ui/webui/options/content_settings_handler.cc
diff --git a/chrome/browser/ui/webui/options/content_settings_handler.cc b/chrome/browser/ui/webui/options/content_settings_handler.cc
index c76998c5d97f75cf03a2432f17a6e23f3448656e..56afc4e7d8d15f3666c6d97fd65e3d8771de1c63 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/content_settings_handler.cc
@@ -790,6 +790,7 @@ void ContentSettingsHandler::OnContentSettingChanged(
     const ContentSettingsPattern& primary_pattern,
     const ContentSettingsPattern& secondary_pattern,
     ContentSettingsType content_type,
+    ContentSetting previous_value,
     std::string resource_identifier) {
   const ContentSettingsDetails details(
       primary_pattern, secondary_pattern, content_type, resource_identifier);