Add Cloud KMS based secret storage

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=147791972

java/google/registry/model/server/KmsSecret.java

@@ -0,0 +1,57 @@
+// Copyright 2017 The Nomulus 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.model.server;
+
+import static google.registry.model.common.EntityGroupRoot.getCrossTldKey;
+import static google.registry.model.ofy.Ofy.RECOMMENDED_MEMCACHE_EXPIRATION;
+
+import com.googlecode.objectify.Key;
+import com.googlecode.objectify.annotation.Cache;
+import com.googlecode.objectify.annotation.Entity;
+import com.googlecode.objectify.annotation.Id;
+import com.googlecode.objectify.annotation.Parent;
+import google.registry.model.ImmutableObject;
+import google.registry.model.annotations.ReportedOn;
+import google.registry.model.common.EntityGroupRoot;
+
+/** Pointer to the latest {@link KmsSecretRevision}. */
+@Entity
+@ReportedOn
+@Cache(expirationSeconds = RECOMMENDED_MEMCACHE_EXPIRATION)
+public class KmsSecret extends ImmutableObject {
+
+  /** The unique name of this {@link KmsSecret}. */
+  @Id String name;
+
+  @Parent Key<EntityGroupRoot> parent = getCrossTldKey();
+
+  /** The pointer to the latest {@link KmsSecretRevision}. */
+  Key<KmsSecretRevision> latestRevision;
+
+  public String getName() {
+    return name;
+  }
+
+  public Key<KmsSecretRevision> getLatestRevision() {
+    return latestRevision;
+  }
+
+  public static KmsSecret create(String name, KmsSecretRevision latestRevision) {
+    KmsSecret instance = new KmsSecret();
+    instance.name = name;
+    instance.latestRevision = Key.create(latestRevision);
+    return instance;
+  }
+}