[sync] skeleton implementation of TypedURLSyncBridge

components/sync/driver/sync_driver_switches.cc

Index: components/sync/driver/sync_driver_switches.cc
diff --git a/components/sync/driver/sync_driver_switches.cc b/components/sync/driver/sync_driver_switches.cc
index e2c08a990419bc1711cf4ada5de3523334ca7e5a..74e4907c707153de1917b712243d0641c56770bf 100644
--- a/components/sync/driver/sync_driver_switches.cc
+++ b/components/sync/driver/sync_driver_switches.cc
@@ -46,4 +46,8 @@ const base::Feature kSyncUSSDeviceInfo{"EnableSyncUSSDeviceInfo",
 const base::Feature kSyncUSSAutocomplete{"SyncUSSAutocomplete",
                                          base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables USS implementation of typed URL datatype.
+const base::Feature kSyncUSSTypedURL{"SyncUSSTypedURL",
+                                     base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace switches