(Re-)introduce AncestorThrottle to handle 'X-Frame-Options'.

components/error_page/common/localized_error.cc

Index: components/error_page/common/localized_error.cc
diff --git a/components/error_page/common/localized_error.cc b/components/error_page/common/localized_error.cc
index 9d09b9277bfefcd18b2bac72c21c504d5118b2a4..59c65161cf39dcfb568df7bd5aa63f556444a075 100644
--- a/components/error_page/common/localized_error.cc
+++ b/components/error_page/common/localized_error.cc
@@ -82,6 +82,7 @@ struct LocalizedErrorMap {
   int buttons; // Which buttons if any to show.
 };
 
+// clang-format off
 const LocalizedErrorMap net_error_options[] = {
   {net::ERR_TIMED_OUT,
    IDS_ERRORPAGES_HEADING_NOT_AVAILABLE,
@@ -305,7 +306,14 @@ const LocalizedErrorMap net_error_options[] = {
    SUGGEST_NONE,
    SHOW_NO_BUTTONS,
   },
+  {net::ERR_BLOCKED_BY_RESPONSE,
+   IDS_ERRORPAGES_HEADING_BLOCKED,
+   IDS_ERRORPAGES_SUMMARY_CONNECTION_REFUSED,
+   SUGGEST_NONE,
+   SHOW_NO_BUTTONS
+  },
 };
+// clang-format on
 
 // Special error page to be used in the case of navigating back to a page
 // generated by a POST.  LocalizedError::HasStrings expects this net error code