When a user logs into sync, the appropriate cookies are retrieved so that

chrome/common/chrome_switches.h

 // 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.
 
 // Defines all the command-line switches used by Chrome.
 
 #ifndef CHROME_COMMON_CHROME_SWITCHES_H_
 #define CHROME_COMMON_CHROME_SWITCHES_H_
 #pragma once
 
@@ skipping 95 matching lines @@
 extern const char kDiskCacheSize[];
 extern const char kDnsLogDetails[];
 extern const char kDnsPrefetchDisable[];
 extern const char kDnsServer[];
 extern const char kDomAutomationController[];
 extern const char kDumpHistogramsOnExit[];
 extern const char kEnableAccelerated2dCanvas[];
 extern const char kEnableAcceleratedPlugins[];
 extern const char kEnableAeroPeekTabs[];
 extern const char kEnableAuthNegotiatePort[];
+extern const char kDisableAutoLogin[];
 extern const char kEnableClearServerData[];
 extern const char kEnableClickToPlay[];
 extern const char kEnableCloudPrintProxy[];
 extern const char kEnableCloudPrint[];
 extern const char kEnableCompactNavigation[];
 extern const char kEnableCompositeToTexture[];
 extern const char kEnableConnectBackupJobs[];
 extern const char kEnableCrxlessWebApps[];
 extern const char kEnableDhcpWpad[];
 extern const char kEnableDNSCertProvenanceChecking[];
@@ skipping 225 matching lines @@
 bool IsPrintPreviewEnabled();
 
 bool IsInBrowserThumbnailingEnabled();
 
 // DON'T ADD RANDOM STUFF HERE. Put it in the main section above in
 // alphabetical order, or in one of the ifdefs (also in order in each section).
 
 }  // namespace switches
 
 #endif  // CHROME_COMMON_CHROME_SWITCHES_H_