Fix a bug where redirect chain gets lost on process swap.

chrome/test/data/extensions/api_test/webrequest/test_blocking.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var pass = chrome.test.callbackPass;
 
 // Constants as functions, not to be called until after runTests.
 function getURLEchoUserAgent() {
   return getServerURL('echoheader?User-Agent');
 }
@@ skipping 108 matching lines @@
         ["onBeforeRequest", "onBeforeSendHeaders", "onSendHeaders",
          "onHeadersReceived", "onErrorOccurred"]
       ],
       {},  // filter
       ["blocking"]);
     navigateAndWait(getURLHttpSimpleLoad());
   },
 
   // Navigates to a page with a blocking handler that redirects to a different
   // page.
-  // TODO(mpcomplete): We should see an onBeforeRedirect as well, but our
-  // process switching logic cancels the original redirect request and
-  // starts a new one instead. See http://crbug.com/79520.

[Matt Perry, 2011/12/03 00:30:22]

Regarding new tests, come to think of it, this is exactly the sort of test I
would write for this change. Maybe it's enough?

[Charlie Reis, 2011/12/03 01:39:56]

This does help as a high-level regression test.  I was thinking something like
the tests in resource_dispatcher_host_unittest.cc to help document how a
cross-process redirect is supposed to look.  If you want to wait to add that
until we turn on the feature, I suppose that's ok.

   function complexLoadRedirected() {
     expect(
       [  // events
         { label: "onBeforeRequest-1",
           event: "onBeforeRequest",
           details: {
             url: getURL("complexLoad/a.html"),
             frameUrl: getURL("complexLoad/a.html")
           },
           retval: {redirectUrl: getURL("simpleLoad/a.html")}
         },
-        { label: "onErrorOccurred-1",
-          event: "onErrorOccurred",
+        { label: "onBeforeRedirect",
+          event: "onBeforeRedirect",
           details: {
             url: getURL("complexLoad/a.html"),
+            redirectUrl: getURL("simpleLoad/a.html"),
+            statusLine: "",
+            statusCode: -1,
             fromCache: false,
-            error: "net::ERR_ABORTED"
-            // Request to chrome-extension:// url has no IP.
-          }
+          },
         },
         { label: "onBeforeRequest-2",
           event: "onBeforeRequest",
           details: {
             url: getURL("simpleLoad/a.html"),
             frameUrl: getURL("simpleLoad/a.html"),
           },
         },
         { label: "onResponseStarted",
           event: "onResponseStarted",
@@ skipping 10 matching lines @@
           details: {
             url: getURL("simpleLoad/a.html"),
             fromCache: false,
             statusCode: 200,
             statusLine: "HTTP/1.1 200 OK",
             // Request to chrome-extension:// url has no IP.
           }
         },
       ],
       [  // event order
-        ["onBeforeRequest-1", "onErrorOccurred-1", "onBeforeRequest-2",
+        ["onBeforeRequest-1", "onBeforeRedirect", "onBeforeRequest-2",
          "onResponseStarted", "onCompleted"],
       ],
       {}, // filter
       ["blocking"]);
     navigateAndWait(getURL("complexLoad/a.html"));
   },
 
   // Loads a testserver page that echoes the User-Agent header that was
   // sent to fetch it. We modify the outgoing User-Agent in
   // onBeforeSendHeaders, so we should see that modified version.
@@ skipping 433 matching lines @@
     // Check the page content for our modified User-Agent string.
     navigateAndWait(getURL("simpleLoad/a.html"), function() {
         var req = new XMLHttpRequest();
         var asynchronous = false;
         req.open("GET", getURLHttpXHRData(), asynchronous);
         req.send(null);
         navigateAndWait(getURL("complexLoad/b.jpg"));
     });
   },
 ]);