Fix NetErrorTabHelper with PlzNavigate.

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index b95c691e3975168323163d65aa0197dbfcc15462..cd75c0ffbc6a252bda93a53090708c90d00ddfdd 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -18,6 +18,7 @@
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/url_constants.h"
 #include "net/url_request/redirect_info.h"
 #include "url/gurl.h"
 #include "url/url_constants.h"
@@ -461,7 +462,14 @@ void NavigationHandleImpl::DidCommitNavigation(
   render_frame_host_ = render_frame_host;
   is_same_page_ = same_page;
 
-  state_ = net_error_code_ == net::OK ? DID_COMMIT : DID_COMMIT_ERROR_PAGE;
+  // If an error page reloads, net_error_code might be 200 but we still want to

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

nit: no "we" in comments?

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

I realize some people think it's unambiguous in some situations, but I think in
this case it's not.

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

Acknowledged.

+  // count it as an error page.
+  if (params.base_url.spec() == kUnreachableWebDataURL ||

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

When we reload the error page, do we know at the start of the navigation that
we're loading kUnreachableWebDataURL, or just at commit time? If at the start,
should we modify IsErrorPage so that it returns true also when we're trying to
load kUnreachableWebDataURL?

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

It's not known at the start (because the url is the what the user typed). Only
when the commit IPC comes does it have the base url to identify it as an error
page. 

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

Acknowledged.

+      net_error_code_ != net::OK) {
+    state_ = DID_COMMIT_ERROR_PAGE;
+  } else {
+    state_ = DID_COMMIT;
+  }
 }
 
 NavigationThrottle::ThrottleCheckResult