Supervised users: Add a cmdline flag and about:flags entry to enable the host blacklist

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 64b03370d5e46141e2ef0519b9cd0f036916ed39..38a6e1cdc4140e3623a30345607dfafc7eec943d 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -604,6 +604,10 @@ const char kEnableStreamlinedHostedApps[]   = "enable-streamlined-hosted-apps";
 // Enables the suggestions service.
 const char kEnableSuggestionsService[]      = "enable-suggestions-service";
 
+// Enables the supervised user host blacklist.
+const char kEnableSupervisedUserBlacklist[] =
+    "enable-supervised-user-blacklist";
+
 // Enables synced notifications.
 const char kEnableSyncSyncedNotifications[] =
     "enable-sync-synced-notifications";