Fix NetErrorTabHelper with PlzNavigate.

content/test/web_contents_observer_sanity_checker.cc

Index: content/test/web_contents_observer_sanity_checker.cc
diff --git a/content/test/web_contents_observer_sanity_checker.cc b/content/test/web_contents_observer_sanity_checker.cc
index e105985297b0aee72cec381d03542c6fcb485ce2..1d85380fc7827c17a154e04b50c26f26e3e561ce 100644
--- a/content/test/web_contents_observer_sanity_checker.cc
+++ b/content/test/web_contents_observer_sanity_checker.cc
@@ -201,9 +201,6 @@ void WebContentsObserverSanityChecker::DidFinishNavigation(
   CHECK(!(navigation_handle->HasCommitted() &&
           !navigation_handle->IsErrorPage()) ||
         navigation_handle->GetNetErrorCode() == net::OK);
-  CHECK(!(navigation_handle->HasCommitted() &&
-          navigation_handle->IsErrorPage()) ||
-        navigation_handle->GetNetErrorCode() != net::OK);

[clamy, 2016/09/19 11:46:44]

Rather than removing this check, can we expend it to cover
navigation_handle->GetNetErrorCode() != net::OK || rul = kUnreachableUrl? I
think these are the only two cases where we can have an error page.

[jam, 2016/09/19 14:19:40]

if you mean navigation_handle->GetURL(), it'll be the URL of the page the user
navigated to, and not the error page. base_url isn't exposed at this point.

[clamy, 2016/09/19 15:27:11]

Acknowledged.

   CHECK_EQ(navigation_handle->GetWebContents(), web_contents());
 
   CHECK(!navigation_handle->HasCommitted() ||