Abstract KMS code with KmsConnection and create a fake KmsConnection

This simplifies the tests for KmsKeyring and KmsUpdater.

This is a followup to []

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148496758

java/google/registry/keyring/kms/EncryptResponse.java

@@ -0,0 +1,41 @@
+// 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.keyring.kms;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * A value type class containing a Cloud KMS encrypted and encoded ciphertext, and the name of the
+ * CryptoKeyVersion used to encrypt it.
+ */
+@AutoValue
+abstract class EncryptResponse {
+
+  static EncryptResponse create(
+      com.google.api.services.cloudkms.v1beta1.model.EncryptResponse cloudKmsEncryptResponse) {
+    return new AutoValue_EncryptResponse(
+        cloudKmsEncryptResponse.getCiphertext(), cloudKmsEncryptResponse.getName());
+  }
+
+  @VisibleForTesting
+  static EncryptResponse create(String ciphertext, String cryptoKeyVersionName) {
+    return new AutoValue_EncryptResponse(ciphertext, cryptoKeyVersionName);
+  }
+
+  abstract String ciphertext();
+
+  abstract String cryptoKeyVersionName();
+}