Rollback feature is taken out of the flag.

chromeos/chromeos_switches.h

Index: chromeos/chromeos_switches.h
diff --git a/chromeos/chromeos_switches.h b/chromeos/chromeos_switches.h
index 43b66b9bd1b1d5ecef719c776ae81b3bca49533d..137e62bc81bc7ea667633b19ebe68aea1e8bc6e6 100644
--- a/chromeos/chromeos_switches.h
+++ b/chromeos/chromeos_switches.h
@@ -38,6 +38,7 @@ CHROMEOS_EXPORT extern const char kDisableNetworkPortalNotification[];
 CHROMEOS_EXPORT extern const char kDisableNewChannelSwitcherUI[];
 CHROMEOS_EXPORT extern const char kDisableNewKioskUI[];
 CHROMEOS_EXPORT extern const char kDisableOfficeEditingComponentApp[];
+CHROMEOS_EXPORT extern const char kDisableRollbackOption[];
 CHROMEOS_EXPORT extern const char kDisableVolumeAdjustSound[];
 CHROMEOS_EXPORT extern const char kEnableCarrierSwitching[];
 CHROMEOS_EXPORT extern const char kEnableChromeVoxNext[];
@@ -48,7 +49,6 @@ CHROMEOS_EXPORT extern const char kEnableFirstRunUITransitions[];
 CHROMEOS_EXPORT extern const char kEnableKioskMode[];
 CHROMEOS_EXPORT extern const char kEnableNetworkPortalNotification[];
 CHROMEOS_EXPORT extern const char kEnableRequestTabletSite[];
-CHROMEOS_EXPORT extern const char kEnableRollbackOption[];
 CHROMEOS_EXPORT extern const char kEnableTouchpadThreeFingerClick[];
 CHROMEOS_EXPORT extern const char kEnableVideoPlayerChromecastSupport[];
 CHROMEOS_EXPORT extern const char kEnterpriseEnableForcedReEnrollment[];