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

chrome/browser/renderer_host/chrome_url_request_user_data.cc

 // 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.
 
 #include "chrome/browser/renderer_host/chrome_url_request_user_data.h"
 
 namespace {
 
 const char* const kKeyName = "chrome_url_request_user_data";
 
 }  // namespace
 
 ChromeURLRequestUserData::ChromeURLRequestUserData()
     : is_prerender_(false) {
 }
 
 // static
 ChromeURLRequestUserData* ChromeURLRequestUserData::Get(
     const net::URLRequest* request) {
   DCHECK(request);
   return static_cast<ChromeURLRequestUserData*>(request->GetUserData(kKeyName));
 }
 
 // static
 ChromeURLRequestUserData* ChromeURLRequestUserData::Create(
     net::URLRequest* request) {
   DCHECK(request);
-  DCHECK(!Get(request));
+  // TODO(mpcomplete): since we're reusing an old URLRequest, this DCHECK
+  // gets hit. We should add a way to clear the UserData for retargeted
+  // requests.
+  //DCHECK(!Get(request));
   ChromeURLRequestUserData* user_data = new ChromeURLRequestUserData();
   request->SetUserData(kKeyName, user_data);
   return user_data;
 }