Add extra flow logic hooks for info and update

This CL adds the hooks necessary to implement TLD-specific flow info and update flow logic. Usage of the hooks follows in a separate CL.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=130108832

java/google/registry/flows/domain/RegistryExtraFlowLogic.java

@@ -0,0 +1,45 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.flows.domain;
+
+import google.registry.flows.EppException;
+import google.registry.model.domain.DomainResource;
+import google.registry.model.eppinput.EppInput;
+import java.util.List;
+import org.joda.time.DateTime;
+
+/**
+ * Interface for classes which provide extra registry logic for things like TLD-specific rules and
+ * discounts.
+ */
+public interface RegistryExtraFlowLogic {
+
+  /** Get the flags to be passed to the client in the EPP flags extension. */
+  public List<String> getFlags(
+      DomainResource domainResource, String clientIdentifier, DateTime asOfDate);
+
+  /**
+   * Add and remove flags passed via the EPP flags extension. Any changes should not be persisted to
+   * Datastore until commitAdditionalDomainUpdates is called. Name suggested by Benjamin McIlwain.
+   */
+  public void performAdditionalDomainUpdateLogic(
+      DomainResource domainResource,
+      String clientIdentifier,
+      DateTime asOfDate,
+      EppInput eppInput) throws EppException;
+
+  /** Commit any changes made as a result of a call to performAdditionalDomainUpdateLogic(). */
+  public void commitAdditionalDomainUpdates();
+}