suppress user/password dialog when re-enabling sync

chrome/browser/sync/sync_prefs.h

Index: chrome/browser/sync/sync_prefs.h
diff --git a/chrome/browser/sync/sync_prefs.h b/chrome/browser/sync/sync_prefs.h
index b6bdfc111caf653fdddc8c60f4e0e49fa7605bae..3256ca8f26afd44b4c0dc92267808119d6e3b118 100644
--- a/chrome/browser/sync/sync_prefs.h
+++ b/chrome/browser/sync/sync_prefs.h
@@ -95,9 +95,17 @@ class SyncPrefs : public base::SupportsWeakPtr<SyncPrefs>,
   // This pref is set outside of sync.
   bool IsManaged() const;
 
+  // Use this encryption bootstrap token once already syncing.
   std::string GetEncryptionBootstrapToken() const;
   void SetEncryptionBootstrapToken(const std::string& token);
 
+#if defined(OS_CHROMEOS)
+  // Use this spare bootstrap token only when setting up sync for the first
+  // time.
+  std::string GetSpareBootstrapToken() const;
+  void SetSpareBootstrapToken(const std::string& token);
+#endif
+
   // InvalidationVersionTracker implementation.
   virtual sync_notifier::InvalidationVersionMap
       GetAllMaxVersions() const OVERRIDE;