[Sync] Split encryption state and logic out of PSS and SBHI.

components/sync/driver/sync_service.h

Index: components/sync/driver/sync_service.h
diff --git a/components/sync/driver/sync_service.h b/components/sync/driver/sync_service.h
index 364ec9981be1d6f86998191268f7684ce33bb7dc..84691ad796d03919bdcce604d46d6dce0414d9cc 100644
--- a/components/sync/driver/sync_service.h
+++ b/components/sync/driver/sync_service.h
@@ -38,6 +38,24 @@ class TypeDebugInfoObserver;
 struct SyncStatus;
 struct UserShare;
 
+// Events in ClearServerData flow to be recorded in histogram. Existing
+// constants should not be deleted or reordered. New ones shold be added at the
+// end, before CLEAR_SERVER_DATA_MAX.
+enum ClearServerDataEvents {
+  // ClearServerData started after user switched to custom passphrase.
+  CLEAR_SERVER_DATA_STARTED,
+  // DataTypeManager reported that catchup configuration failed.
+  CLEAR_SERVER_DATA_CATCHUP_FAILED,
+  // ClearServerData flow restarted after browser restart.
+  CLEAR_SERVER_DATA_RETRIED,
+  // Success.
+  CLEAR_SERVER_DATA_SUCCEEDED,
+  // Client received RECET_LOCAL_SYNC_DATA after custom passphrase was enabled
+  // on different client.
+  CLEAR_SERVER_DATA_RESET_LOCAL_DATA_RECEIVED,
+  CLEAR_SERVER_DATA_MAX
+};
+
 // UIs that need to prevent Sync startup should hold an instance of this class
 // until the user has finished modifying sync settings. This is not an inner
 // class of SyncService to enable forward declarations.