Remove the use_objc_header rule warning. Add a generic migration warning to objc_proto_library without the portable_proto_filters attribute.

PiperOrigin-RevId: 153189663
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProtoLibrary.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProtoLibrary.java
index 031a5a1..6b2ba5a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProtoLibrary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProtoLibrary.java
@@ -39,6 +39,9 @@
     if (attributes.hasPortableProtoFilters()) {
       return createProtobufTarget(ruleContext);
     } else {
+      ruleContext.ruleWarning("The usage of objc_proto_library without the portable_proto_filters "
+          + "attribute has been deprecated with a deadline to migrate set to June 30th. Please "
+          + "refer to b/37274743 for more information.");
       return createProtocolBuffers2Target(ruleContext);
     }
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ProtoAttributes.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ProtoAttributes.java
index f379f0b..e620f32 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ProtoAttributes.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ProtoAttributes.java
@@ -140,12 +140,6 @@
       if (getProtoFiles().isEmpty()) {
         ruleContext.throwWithRuleError(NO_PROTOS_ERROR);
       }
-
-      if (!usesObjcHeaderNames()) {
-        ruleContext.ruleWarning(
-            "As part of the migration process, it is recommended to enable "
-                + "use_objc_header_names. Please refer to b/29368416 for more information.");
-      }
       if (hasObjcProtoLibraryDependencies()) {
         ruleContext.throwWithRuleError(OBJC_PROTO_LIB_DEP_IN_PROTOCOL_BUFFERS2_DEPS_ERROR);
       }