Reapply r19950. Turns out it wasn't at fault for breaking the vista tests.

chrome/browser/dom_ui/chrome_url_data_manager.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H__
 #define BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H__
 
 #include <map>
 #include <string>
 
@@ skipping 94 matching lines @@
   // Translate a chrome resource URL into a local file path if there is one.
   // Returns false if there is no file handler for this URL
   static bool URLToFilePath(const GURL& url, std::wstring* file_path);
 
   // Called by the job when it's starting up.
   // Returns false if |url| is not a URL managed by this object.
   bool StartRequest(const GURL& url, URLRequestChromeJob* job);
   // Remove a request from the list of pending requests.
   void RemoveRequest(URLRequestChromeJob* job);
 
+  // Returns true if the job exists in |pending_requests_|. False otherwise.
+  // Called by ~URLRequestChromeJob to verify that |pending_requests_| is kept
+  // up to date.
+  bool HasPendingJob(URLRequestChromeJob* job) const;
+
   // Sent by Request::SendResponse.
   void DataAvailable(RequestID request_id,
                      scoped_refptr<RefCountedBytes> bytes);
 
   // File sources of data, keyed by source name (e.g. "inspector").
   typedef std::map<std::string, std::wstring> FileSourceMap;
   FileSourceMap file_sources_;
 
   // Custom sources of data, keyed by source path (e.g. "favicon").
   typedef std::map<std::string, scoped_refptr<DataSource> > DataSourceMap;
@@ skipping 20 matching lines @@
 extern ChromeURLDataManager chrome_url_data_manager;
 
 // Register our special URL handler under our special URL scheme.
 // Must be done once at startup.
 void RegisterURLRequestChromeJob();
 
 // Undoes the registration done by RegisterURLRequestChromeJob.
 void UnregisterURLRequestChromeJob();
 
 #endif  // BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H__