Enforced that upb_msg lives in an Arena only, and other simplifying.

upb_msg was trying to be general enough that it could either live in
an arena or be allocated with malloc()/free().  This was too much
complexity for too little benefit.  We should commit to just saying
that upb_msg is arena-only.

I also ripped out the code to glue upb_msg to the existing
handlers-based encoder/decoder.  upb_msg has its own, small, simple
encoder/decoder.  I'm trying to whittle down upb_msg to a small
and simple core.

I updated the Lua extension for these changes.  Lua needs some more
work to properly create arenas per message.  For now I just created
a single global arena.

1 files changed, 1 insertions, 1 deletions

diff --git a/upb/structs.int.h b/upb/structs.int.h
index 242155b..6bc502e 100644
--- a/upb/structs.int.h
+++ b/upb/structs.int.h
@@ -11,7 +11,7 @@ struct upb_array {
   void *data;   /* Each element is element_size. */
   size_t len;   /* Measured in elements. */
   size_t size;  /* Measured in elements. */
-  upb_alloc *alloc;
+  upb_arena *arena;
 };
 
 #endif  /* UPB_STRUCTS_H_ */