[Sync] Add bookmark move tests.

sync/test/fake_server/fake_server.h

Index: sync/test/fake_server/fake_server.h
diff --git a/sync/test/fake_server/fake_server.h b/sync/test/fake_server/fake_server.h
index f6da254305dcb8a9259b5e78a1aaf5a5239a6154..e01de194d3e6e0a5e037ea8f6729e163b5e2eea9 100644
--- a/sync/test/fake_server/fake_server.h
+++ b/sync/test/fake_server/fake_server.h
@@ -81,6 +81,10 @@ class FakeServer {
   bool ModifyEntitySpecifics(const std::string& id,
                              const sync_pb::EntitySpecifics& updated_specifics);
 
+  bool ModifyBookmarkEntity(const std::string& id,
+                            const std::string& parent_id,
+                            const sync_pb::EntitySpecifics& updated_specifics);
+
   // Clears server data simulating a "dashboard stop and clear" and sets a new
   // store birthday.
   void ClearServerData();