(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,

[clamy, 2016/12/09 17:14:01]

Does this mean net::ERR_BLOCKED_BY_RESPONSE will display an error page? If so,
is that what we want or do we want to display a blank frame?

[arthursonzogni, 2016/12/13 15:32:13]

Yes, the intent is to display error pages.
The thing is that after in RenderFrameImpl::LoadNavigationErrorPage, the
net::ERR_BLOCKED_BY_RESPONSE error page is transformed into a blank page because
there is a problem for the moment with how error pages are handled in Chrome.
The URL of the page that fails to load is committed in the browser, which causes
problems.

It would be nice if we could display an error page. That's what we want in the
future. Currently a blank page is displayed. That's the current chrome behavior
and this patch doesn't change this.

+   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