Deletes CODEC fields now that they are no longer needed.

PiperOrigin-RevId: 187397314
diff --git a/src/main/java/com/google/devtools/build/lib/cmdline/PackageIdentifier.java b/src/main/java/com/google/devtools/build/lib/cmdline/PackageIdentifier.java
index fdf574f..d8bf3bf 100644
--- a/src/main/java/com/google/devtools/build/lib/cmdline/PackageIdentifier.java
+++ b/src/main/java/com/google/devtools/build/lib/cmdline/PackageIdentifier.java
@@ -18,7 +18,7 @@
 import com.google.common.collect.ComparisonChain;
 import com.google.common.collect.Interner;
 import com.google.devtools.build.lib.concurrent.BlazeInterners;
-import com.google.devtools.build.lib.skyframe.serialization.ObjectCodec;
+import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -33,12 +33,10 @@
  * the workspace name "". Other repositories can be named in the WORKSPACE file. These workspaces
  * are prefixed by {@literal @}.
  */
+@AutoCodec
 @Immutable
 public final class PackageIdentifier
     implements Comparable<PackageIdentifier>, Serializable, SkylarkValue {
-
-  public static final ObjectCodec<PackageIdentifier> CODEC = new PackageIdentifierCodec();
-
   private static final Interner<PackageIdentifier> INTERNER = BlazeInterners.newWeakInterner();
 
   public static PackageIdentifier create(String repository, PathFragment pkgName)
@@ -46,6 +44,7 @@
     return create(RepositoryName.create(repository), pkgName);
   }
 
+  @AutoCodec.Instantiator
   public static PackageIdentifier create(RepositoryName repository, PathFragment pkgName) {
     return INTERNER.intern(new PackageIdentifier(repository, pkgName));
   }