Replace KeystoreKeyring with KmsKeystore comparison

Replace KeystoreKeyring with ComparatorKeyring between KeystoreKeyring and
KmsKeystore. In the opensource version, will replace DummyKeyring with
KmsKeyring directly.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=152893767

java/google/registry/keyring/api/ComparatorKeyring.java

@@ -21,6 +21,8 @@ import google.registry.util.ComparingInvocationHandler;
 import google.registry.util.FormattingLogger;
 
 import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Objects;
@@ -43,7 +45,7 @@ import org.bouncycastle.openpgp.PGPPublicKey;
  * <p>If both keyrings threw exceptions, there is no check whether the exeptions are the same. The
  * assumption is that an error happened in both, but they might report that error differently.
  */
-final class ComparatorKeyring extends ComparingInvocationHandler<Keyring> {
+public final class ComparatorKeyring extends ComparingInvocationHandler<Keyring> {
 
   @VisibleForTesting
   static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
@@ -98,6 +100,14 @@ final class ComparatorKeyring extends ComparingInvocationHandler<Keyring> {
     return super.stringifyResult(method, a);
   }
 
+  @Override
+  protected String stringifyThrown(Method method, Throwable throwable) {
+    StringWriter stringWriter = new StringWriter();
+    PrintWriter printWriter = new PrintWriter(stringWriter);
+    throwable.printStackTrace(printWriter);
+    return String.format("%s\nStack trace:\n%s", throwable.toString(), stringWriter.toString());
+  }
+
   // .equals implementation for PGP types.
 
   @VisibleForTesting

java/google/registry/keyring/kms/KeyringModule.java

@@ -0,0 +1,34 @@
+// 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 dagger.Module;
+import dagger.Provides;
+
+import google.registry.keyring.api.Keyring;
+
+import javax.inject.Singleton;
+
+/** Dagger module for {@link Keyring} */
+@Module
+public final class KeyringModule {
+
+  @Provides
+  @Singleton
+  // TODO(b/35810650): return kmsKeyring directly once comparison period is over.
+  public static Keyring provideKeyring(KmsKeyring kmsKeyring) {
+    return kmsKeyring;
+  }
+}