suppress user/password dialog when re-enabling sync

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 9df8bb8ee7d126b8304d3aa76559f0a835a8a6af..33b0d58d3cbf683abb326d38e6e237527ff161d7 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1646,6 +1646,10 @@ const char kReportDeviceActivityTimes[] = "device_status.report_activity_times";
 // The local state pref that stores device activity times before reporting
 // them to the policy server.
 extern const char kDeviceActivityTimes[] = "device_status.activity_times";
+
+// A string that is used to store first-time sync startup after once sync is
+// disabled. This will be refreshed every sign-in.
+const char kSyncSpareBootstrapToken[] = "sync.spare_bootstrap_token";
 #endif
 
 // Whether there is a Flash version installed that supports clearing LSO data.