cache.h: add repository argument to oid_object_info

Add a repository argument to allow the callers of oid_object_info
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index d44b4f9..409da4e 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -94,7 +94,7 @@ static int show_tree(const struct object_id *oid, struct strbuf *base,
 			char size_text[24];
 			if (!strcmp(type, blob_type)) {
 				unsigned long size;
-				if (oid_object_info(oid, &size) == OBJ_BAD)
+				if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
 					xsnprintf(size_text, sizeof(size_text),
 						  "BAD");
 				else