Add test case to see if HTTP auth interstitials work nicely with other interstitials

chrome/browser/ui/login/login_prompt.cc

Index: chrome/browser/ui/login/login_prompt.cc
diff --git a/chrome/browser/ui/login/login_prompt.cc b/chrome/browser/ui/login/login_prompt.cc
index 53f68a7b4a8f518502bdf7c005e1aaa274b15769..4af671385261a87cffa45481aa9a662b763e28d5 100644
--- a/chrome/browser/ui/login/login_prompt.cc
+++ b/chrome/browser/ui/login/login_prompt.cc
@@ -509,15 +509,21 @@ void LoginDialogCallback(const GURL& request_url,
     return;
   }
 
+  // For main frame navigations, show a blank interstitial if this is a cross
+  // origin request or if there is an existing interstitial.
   if (is_main_frame &&
-      parent_contents->GetVisibleURL().GetOrigin() != request_url.GetOrigin()) {
+      (parent_contents->GetInterstitialPage() ||

[nasko, 2014/07/17 14:08:44]

Is it correct that we hit this only after proceeding through the first
interstitial?

[meacer, 2014/07/17 22:08:18]

I can't think of any other state where an interstitial would already be shown.

+       parent_contents->GetVisibleURL().GetOrigin() != request_url.GetOrigin())
+      ) {
     // Show a blank interstitial for main-frame, cross origin requests
     // so that the correct URL is shown in the omnibox.
     base::Closure callback = base::Bind(&ShowLoginPrompt,
                                         request_url,
                                         make_scoped_refptr(auth_info),
                                         make_scoped_refptr(handler));
-    // This is owned by the interstitial it creates.
+
+    // This is owned by the interstitial it creates. The new interstitial will
+    // replace existing interstitial, if any.

[nasko, 2014/07/17 14:08:44]

I don't recall the ownership semantics of this. Would we leak the old
interstitial if we replace it with this one?

[meacer, 2014/07/17 22:08:18]

Interstitials clean up themselves on navigation. Since the login interstitial
creates a new navigation, the old one is cleaned up.

     new LoginInterstitialDelegate(parent_contents,
                                   request_url,
                                   callback);