Revert of Remove OneClickSigninHelper since it is no longer used.

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.h

 // Copyright (c) 2012 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 CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 #define CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 
 #include <map>
 #include <set>
 
@@ skipping 74 matching lines @@
     std::string view_id;
   };
 #endif
 
   void AppendStandardResourceThrottles(
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       content::ResourceType resource_type,
       ScopedVector<content::ResourceThrottle>* throttles);
 
+#if defined(ENABLE_ONE_CLICK_SIGNIN)
+  // Append headers required to tell Gaia whether the sync interstitial
+  // should be shown or not.  This header is only added for valid Gaia URLs.
+  void AppendChromeSyncGaiaHeader(
+      net::URLRequest* request,
+      content::ResourceContext* resource_context);
+#endif
+
   scoped_refptr<DownloadRequestLimiter> download_request_limiter_;
   scoped_refptr<SafeBrowsingService> safe_browsing_;
 #if defined(ENABLE_EXTENSIONS)
   scoped_refptr<extensions::UserScriptListener> user_script_listener_;
   std::map<net::URLRequest*, StreamTargetInfo> stream_target_info_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeResourceDispatcherHostDelegate);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_