Test for navigating back to navigation that posts to a cross-site 307 redirect.

content/public/test/browser_test_utils.cc

Index: content/public/test/browser_test_utils.cc
diff --git a/content/public/test/browser_test_utils.cc b/content/public/test/browser_test_utils.cc
index f24c5f4ba08ac33e3fadb40627838b36845638a6..bb8bc6687cdb5460732d75f2d4c94e762bcc2ab5 100644
--- a/content/public/test/browser_test_utils.cc
+++ b/content/public/test/browser_test_utils.cc
@@ -291,12 +291,25 @@ void SetCookieOnIOThread(const GURL& url,
 std::unique_ptr<net::test_server::HttpResponse>
 CrossSiteRedirectResponseHandler(const GURL& server_base_url,
                                  const net::test_server::HttpRequest& request) {
-  std::string prefix("/cross-site/");
-  if (!base::StartsWith(request.relative_url, prefix,
-                        base::CompareCase::SENSITIVE))
+  net::HttpStatusCode http_status_code;
+
+  // Inspect the prefix and extract the remainder of the url into |params|.
+  size_t length_of_chosen_prefix;
+  std::string prefix_302("/cross-site/");
+  std::string prefix_307("/cross-site-307/");

[Charlie Reis, 2016/05/23 20:51:35]

Hmm, this feels like it's growing into a bit of a hack.  I'm curious if we can
avoid it, but maybe it's needed.

Does the ".mock_http_headers" feature give us something we can use here?  I've
seen Alex use it in tests like x-frame-options-deny.html.mock-http-headers. 
Maybe the form could post to a same-site test page that had a 307 redirect to
x.com/echoall in the mock headers?

Maybe that's doomed if it can't handle the test server port?  Or maybe there's
some support for ports?  I see redirect-to-title2.html.mock-http-headers uses
port 4000, though I'm not sure if that's handled properly.

If we have to keep this, it's worth documenting carefully.

[Łukasz Anforowicz, 2016/05/24 19:08:08]

I think it would feel much less like a hack if it there was more consistency
between the 2 cases.  OTOH, I can't think of good options to achieve
consistency:

- Changing "/cross-site/" to "/cross-site-302/" seems bad, because 1) it
requires modifying all the existing tests and 2) it unnecessarily forces tests
to explicitly declare a mode of redirection when they might just want *any*
redirect (and not specifically a 302 or 307).

- Extracting redirect mode / http status from query parameters seems overly
complicated (have to add parsing of query parameters + be careful to preserve
other query parameters (and other url aspects like fragment navigations) after
the redirect).
mock-http-headers won't work, because they are sent back verbatim, and in this
case we need to emit Location: that matches the currently allocated port of
embedder_test_server.
Thanks for the pointer.  It seems that
ResourceDispatcherHostBrowserTest::SetUpOnMainThread doesn't go through the
embedded_test_server, but intercepts http requests via
net::URLRequestMockHTTPJob::AddUrlHandlers.  I am guessing that this is why the
port number can be hardcoded here.
I've added an explanation in the comment above declaration of
content::SetupCrossSiteRedirector.

+  if (base::StartsWith(request.relative_url, prefix_302,
+                       base::CompareCase::SENSITIVE)) {
+    http_status_code = net::HTTP_MOVED_PERMANENTLY;
+    length_of_chosen_prefix = prefix_302.length();
+  } else if (base::StartsWith(request.relative_url, prefix_307,
+                       base::CompareCase::SENSITIVE)) {
+    http_status_code = net::HTTP_TEMPORARY_REDIRECT;
+    length_of_chosen_prefix = prefix_307.length();
+  } else {
+    // Unrecognized prefix - let somebody else handle this request.
     return std::unique_ptr<net::test_server::HttpResponse>();
-
-  std::string params = request.relative_url.substr(prefix.length());
+  }
+  std::string params = request.relative_url.substr(length_of_chosen_prefix);
 
   // A hostname to redirect to must be included in the URL, therefore at least
   // one '/' character is expected.
@@ -316,7 +329,7 @@ CrossSiteRedirectResponseHandler(const GURL& server_base_url,
 
   std::unique_ptr<net::test_server::BasicHttpResponse> http_response(
       new net::test_server::BasicHttpResponse);
-  http_response->set_code(net::HTTP_MOVED_PERMANENTLY);
+  http_response->set_code(http_status_code);
   http_response->AddCustomHeader("Location", redirect_target.spec());
   return std::move(http_response);
 }