(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 ef5bf3c5b006634d5e0cf099ad5bda4a05ba25ec..7979d426a0e210d13100018dc87083ad524146ef 100644
--- a/components/error_page/common/localized_error.cc
+++ b/components/error_page/common/localized_error.cc
@@ -84,6 +84,7 @@ 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,
@@ -313,7 +314,14 @@ 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