diff -r 000000000000 -r 6474c204b198 mobile/android/base/sync/repositories/delegates/RepositorySessionBeginDelegate.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/sync/repositories/delegates/RepositorySessionBeginDelegate.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+/**
+ * One of these two methods is guaranteed to be called after session.begin() is
+ * invoked (possibly during the invocation). The callback will be invoked prior
+ * to any other RepositorySession callbacks.
+ *
+ * @author rnewman
+ *
+ */
+public interface RepositorySessionBeginDelegate {
+  public void onBeginFailed(Exception ex);
+  public void onBeginSucceeded(RepositorySession session);
+  public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService executor);
+}