Scope down lastTransferTime to only ContactResource, DomainResource

and HostResource.

DomainApplication is not transferable and has no need for this
field. HostResource needs it because it can be transferred with
a domain.

This is all in service of removing the ofy().load() inside of
host's cloneProjectedAtTime.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139346925

java/google/registry/model/domain/DomainResource.java

@@ -162,6 +162,14 @@ public class DomainResource extends DomainBase
   @XmlTransient
   TransferData transferData;
 
+  /**
+   * The time that this resource was last transferred.
+   *
+   * <p>Can be null if the resource has never been transferred.
+   */
+  @XmlElement(name = "trDate")
+  DateTime lastTransferTime;
+
   public ImmutableSet<String> getSubordinateHosts() {
     return nullToEmptyImmutableCopy(subordinateHosts);
   }
@@ -203,6 +211,11 @@ public class DomainResource extends DomainBase
     return Optional.fromNullable(transferData).or(TransferData.EMPTY);
   }
 
+  @Override
+  public DateTime getLastTransferTime() {
+    return lastTransferTime;
+  }
+
   @Override
   public String getForeignKey() {
     return fullyQualifiedDomainName;
@@ -462,5 +475,12 @@ public class DomainResource extends DomainBase
       getInstance().transferData = transferData;
       return thisCastToDerived();
     }
+
+    @Override
+    public Builder setLastTransferTime(DateTime lastTransferTime) {
+      getInstance().lastTransferTime = lastTransferTime;
+      return thisCastToDerived();
+    }
   }
 }
+