Move resolv_init out and make callbacks of libnetd_resolv global

1. Revise init flow of libnetd_resolv
   - A better and generic design for it
2. Rename and make callbacks from netd global
   - libnetd_resolv has multiple components need to use it
   - res* component could use it easily

Bug: 126141549
Test: built, flashed, booted
      system/netd/tests/runtests.sh pass

Change-Id: Iacb4fd708a26fd9c9139a606f0320fc12b4fc7e1
diff --git a/resolv/include/netd_resolv/resolv.h b/resolv/include/netd_resolv/resolv.h
index 2e65370..b5518e4 100644
--- a/resolv/include/netd_resolv/resolv.h
+++ b/resolv/include/netd_resolv/resolv.h
@@ -110,7 +110,7 @@
 // TODO: Remove the callback after moving NAT64 prefix discovery out of netd to libnetd_resolv.
 typedef bool (*get_dns64_prefix_callback)(unsigned netid, in6_addr* prefix, uint8_t* prefix_len);
 
-struct dnsproxylistener_callbacks {
+struct ResolverNetdCallbacks {
     check_calling_permission_callback check_calling_permission;
     get_network_context_callback get_network_context;
     get_dns64_prefix_callback get_dns64_prefix;
@@ -150,7 +150,7 @@
 // Delete the cache associated with a certain network
 LIBNETD_RESOLV_PUBLIC void resolv_delete_cache_for_net(unsigned netid);
 
-// Set callbacks to DnsProxyListener, and bring it up.
-LIBNETD_RESOLV_PUBLIC bool resolv_init(const dnsproxylistener_callbacks& callbacks);
+// Set callbacks and bring DnsResolver up.
+LIBNETD_RESOLV_PUBLIC bool resolv_init(const ResolverNetdCallbacks& callbacks);
 
 #endif  // NETD_RESOLV_RESOLV_H