Perform /ListAccounts check before session merge to see if there is a need for session merge at all.

chrome/browser/chromeos/login/oauth2_login_verifier.h

 // Copyright (c) 2013 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_CHROMEOS_LOGIN_OAUTH2_LOGIN_VERIFIER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_OAUTH2_LOGIN_VERIFIER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 35 matching lines @@
     // Invoked when post-merge session verification fails.
     virtual void OnListAccountsFailure(bool connection_error) = 0;
   };
 
   OAuth2LoginVerifier(OAuth2LoginVerifier::Delegate* delegate,
                       net::URLRequestContextGetter* system_request_context,
                       net::URLRequestContextGetter* user_request_context,
                       const std::string& oauthlogin_access_token);
   virtual ~OAuth2LoginVerifier();
 
+  // Initiates verification of GAIA cookies in |profile|'s cookie jar.
+  void VerifyUserCookies(Profile* profile);
+
   // Attempts to restore session from OAuth2 refresh token minting all necesarry
   // tokens along the way (OAuth2 access token, SID/LSID, GAIA service token).
   void VerifyProfileTokens(Profile* profile);
 
  private:
   enum SessionRestoreType {
     RESTORE_UNDEFINED = 0,
     RESTORE_FROM_GAIA_TOKEN = 1,
     RESTORE_FROM_OAUTH2_REFRESH_TOKEN = 2,
   };
@@ skipping 21 matching lines @@
   // Starts OAuthLogin request for GAIA uber-token.
   void StartOAuthLoginForUberToken();
 
   // Attempts to merge session from present |gaia_token_|.
   void StartMergeSession();
 
   // Schedules post merge verification to ensure that browser session restore
   // hasn't stumped over SID/LSID.
   void SchedulePostMergeVerification();
 
-  // Starts post merge request verification.
-  void StartPostRestoreVerification();
+  // Starts GAIA auth cookies (SID/LSID) verification.
+  void StartAuthCookiesVerification();
 
   // Decides how to proceed on GAIA |error|. If the error looks temporary,
   // retries |task| after certain delay until max retry count is reached.
   void RetryOnError(const char* operation_id,
                     const GoogleServiceAuthError& error,
                     const base::Closure& task_to_retry,
                     const ErrorHandler& error_handler);
 
+  // Delays operation defined with |callback| based on the current networking
+  // conditions.
+  bool DelayNetworkCall(const base::Closure& callback);
+
   OAuth2LoginVerifier::Delegate* delegate_;
   scoped_refptr<net::URLRequestContextGetter> system_request_context_;
   scoped_refptr<net::URLRequestContextGetter> user_request_context_;
   scoped_ptr<GaiaAuthFetcher> gaia_fetcher_;
   std::string access_token_;
   std::string gaia_token_;
   scoped_ptr<OAuth2TokenService::Request> login_token_request_;
   // The retry counter. Increment this only when failure happened.
   int retry_count_;
 
   DISALLOW_COPY_AND_ASSIGN(OAuth2LoginVerifier);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_OAUTH2_LOGIN_VERIFIER_H_