Remove duplicate version of lookupSuperordinateDomain() function

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148657943

java/google/registry/flows/host/HostCreateFlow.java

@@ -96,8 +96,8 @@ public final class HostCreateFlow implements TransactionalFlow {
     // The superordinate domain of the host object if creating an in-bailiwick host, or null if
     // creating an external host. This is looked up before we actually create the Host object so
     // we can detect error conditions earlier.
-    Optional<DomainResource> superordinateDomain = Optional.fromNullable(
-        lookupSuperordinateDomain(validateHostName(targetId), now));
+    Optional<DomainResource> superordinateDomain =
+        lookupSuperordinateDomain(validateHostName(targetId), now);
     verifyDomainIsSameRegistrar(superordinateDomain.orNull(), clientId);
     boolean willBeSubordinate = superordinateDomain.isPresent();
     boolean hasIpAddresses = !isNullOrEmpty(command.getInetAddresses());

java/google/registry/flows/host/HostFlowUtils.java

@@ -86,12 +86,12 @@ public class HostFlowUtils {
   }
 
   /** Return the {@link DomainResource} this host is subordinate to, or null for external hosts. */
-  static DomainResource lookupSuperordinateDomain(
+  public static Optional<DomainResource> lookupSuperordinateDomain(
       InternetDomainName hostName, DateTime now) throws EppException {
     Optional<InternetDomainName> tld = findTldForName(hostName);
     if (!tld.isPresent()) {
       // This is an host on a TLD we don't run, therefore obviously external, so we are done.
-      return null;
+      return Optional.absent();
     }
     // This is a subordinate host
     String domainName = Joiner.on('.').join(Iterables.skip(
@@ -100,7 +100,7 @@ public class HostFlowUtils {
     if (superordinateDomain == null || !isActive(superordinateDomain, now)) {
       throw new SuperordinateDomainDoesNotExistException(domainName);
     }
-    return superordinateDomain;
+    return Optional.of(superordinateDomain);
   }
 
   /** Superordinate domain for this hostname does not exist. */

java/google/registry/flows/host/HostUpdateFlow.java

@@ -130,7 +130,7 @@ public final class HostUpdateFlow implements TransactionalFlow {
     String newHostName = firstNonNull(suppliedNewHostName, oldHostName);
     // Note that lookupSuperordinateDomain calls cloneProjectedAtTime on the domain for us.
     Optional<DomainResource> newSuperordinateDomain =
-        Optional.fromNullable(lookupSuperordinateDomain(validateHostName(newHostName), now));
+        lookupSuperordinateDomain(validateHostName(newHostName), now);
     verifyUpdateAllowed(command, existingHost, newSuperordinateDomain.orNull());
     if (isHostRename && loadAndGetKey(HostResource.class, newHostName, now) != null) {
       throw new HostAlreadyExistsException(newHostName);

java/google/registry/rde/imports/RdeHostLinkAction.java

@@ -14,18 +14,14 @@
 
 package google.registry.rde.imports;
 
-import static com.google.common.base.Preconditions.checkState;
+import static google.registry.flows.host.HostFlowUtils.lookupSuperordinateDomain;
 import static google.registry.mapreduce.MapreduceRunner.PARAM_MAP_SHARDS;
-import static google.registry.model.EppResourceUtils.loadByForeignKey;
 import static google.registry.model.ofy.ObjectifyService.ofy;
-import static google.registry.model.registry.Registries.findTldForName;
 import static google.registry.util.PipelineUtils.createJobPath;
 
 import com.google.appengine.tools.mapreduce.Mapper;
-import com.google.common.base.Joiner;
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Iterables;
 import com.google.common.net.InternetDomainName;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.VoidWork;
@@ -135,29 +131,6 @@ public class RdeHostLinkAction implements Runnable {
         throw new HostLinkException(xjcHost.getName(), xjcHost.toString(), e);
       }
     }
-
-    /**
-     * Return the {@link DomainResource} this host is subordinate to, or absent for out of zone
-     * hosts.
-     *
-     * @throws IllegalStateException for hosts without superordinate domains
-     */
-    private static Optional<DomainResource> lookupSuperordinateDomain(
-        InternetDomainName hostName, DateTime now) {
-      Optional<InternetDomainName> tld = findTldForName(hostName);
-      // out of zone hosts cannot be linked
-      if (!tld.isPresent()) {
-        return Optional.absent();
-      }
-      // This is a subordinate host
-      String domainName = Joiner.on('.').join(Iterables.skip(
-          hostName.parts(), hostName.parts().size() - (tld.get().parts().size() + 1)));
-      DomainResource superordinateDomain = loadByForeignKey(DomainResource.class, domainName, now);
-      // Hosts can't be linked if domains import hasn't been run
-      checkState(
-          superordinateDomain != null, "Superordinate domain does not exist: %s", domainName);
-      return Optional.of(superordinateDomain);
-    }
   }
 
   private static class HostLinkException extends RuntimeException {