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

chrome/common/chrome_switches.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/common/chrome_switches.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 
 namespace switches {
@@ skipping 351 matching lines @@
 const char kEnableAcceleratedPlugins[]      = "enable-accelerated-plugins";
 
 // Enables AeroPeek for each tab. (This switch only works on Windows 7).
 const char kEnableAeroPeekTabs[]            = "enable-aero-peek-tabs";
 
 // Enable the inclusion of non-standard ports when generating the Kerberos SPN
 // in response to a Negotiate challenge. See HttpAuthHandlerNegotiate::CreateSPN
 // for more background.
 const char kEnableAuthNegotiatePort[]       = "enable-auth-negotiate-port";
 
+// Disable both pre- and auto-login for services attached to a GAIA account
+// even when the GAIA credentials are available through sync.
+const char kDisableAutoLogin[]              = "disable-auto-login";
+
 // This flag enables UI for clearing server data.  Temporarily in place
 // until there's a server endpoint deployed.
 const char kEnableClearServerData[]         = "enable-clear-server-data";
 
 // Enable click-to-play for blocked plug-ins.
 const char kEnableClickToPlay[]             = "enable-click-to-play";
 
 // This applies only when the process type is "service". Enables the
 // Cloud Print Proxy component within the service process.
 const char kEnableCloudPrintProxy[]         = "enable-cloud-print-proxy";
@@ skipping 793 matching lines @@
 
 // -----------------------------------------------------------------------------
 // DO NOT ADD YOUR CRAP TO THE BOTTOM OF THIS FILE.
 //
 // You were going to just dump your switches here, weren't you? Instead,
 // please put them in alphabetical order above, or in order inside the
 // appropriate ifdef at the bottom. The order should match the header.
 // -----------------------------------------------------------------------------
 
 }  // namespace switches