Remove Arena::CreateMessage.

It has equivalent performance to Arena::Create.

PiperOrigin-RevId: 660086722

src/google/protobuf/arena.h

@@ -176,8 +176,8 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
 
   inline ~Arena() = default;
 
-  // Deprecated. Use Create<T> instead. TODO: depreate OSS version
-  // once internal migration to Arena::Create is done.
+#ifndef PROTOBUF_FUTURE_REMOVE_CREATEMESSAGE
+  // Deprecated. Use Create<T> instead.
   template <typename T, typename... Args>
   ABSL_DEPRECATED("Use Create")
   static T* CreateMessage(Arena* arena, Args&&... args) {
@@ -187,6 +187,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
         "CreateMessage can only construct types that are ArenaConstructable");
     return Create<Type>(arena, std::forward<Args>(args)...);
   }
+#endif  // !PROTOBUF_FUTURE_REMOVE_CREATEMESSAGE
 
   // Allocates an object type T if the arena passed in is not nullptr;
   // otherwise, returns a heap-allocated object.

src/google/protobuf/port_def.inc

@@ -143,6 +143,10 @@ static_assert(PROTOBUF_ABSL_MIN(20230125, 3),
 // Owner: shaod@, gberg@
 #define PROTOBUF_FUTURE_DESCRIPTOR_EXTENSION_DECL 1
 
+// Removes Arena::CreateMessage, as Arena::Create is equivalent
+// Owner: ckennelly@, mkruskal@
+#define PROTOBUF_FUTURE_REMOVE_CREATEMESSAGE 1
+
 #endif
 
 #ifdef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE

src/google/protobuf/port_undef.inc

@@ -84,6 +84,7 @@
 #undef PROTOBUF_FUTURE_BREAKING_CHANGES
 #undef PROTOBUF_FUTURE_DESCRIPTOR_EXTENSION_DECL
 #undef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE
+#undef PROTOBUF_FUTURE_REMOVE_CREATEMESSAGE
 #endif
 
 // Restore macros that may have been #undef'd in port_def.inc.