adb client interface for secure services

This CL exposes a callback-based interface to perform some action for
each resolved pairing/connect service as a function of their hostname,
ip address, and port.

The ADB client can then use this information to either set up secure
connections directly, or to tell the adb host server to do so, or
something.

Bug: 111434128, 119490749

Test: N/A
Exempt-From-Owner-Approval: already approved
Change-Id: I2dd04c322df5b0597859f44703cfd2f3f29fd737
diff --git a/adb/adb_mdns.h b/adb/adb_mdns.h
index e223b1b..cc22581 100644
--- a/adb/adb_mdns.h
+++ b/adb/adb_mdns.h
@@ -23,6 +23,10 @@
 const char* kADBSecurePairingServiceType = "_adb_secure_pairing._tcp";
 const char* kADBSecureConnectServiceType = "_adb_secure_connect._tcp";
 
+const int kADBTransportServiceRefIndex = 0;
+const int kADBSecurePairingServiceRefIndex = 1;
+const int kADBSecureConnectServiceRefIndex = 2;
+
 const char* kADBDNSServices[] = {
         kADBServiceType,
         kADBSecurePairingServiceType,
@@ -30,6 +34,5 @@
 };
 
 const int kNumADBDNSServices = arraysize(kADBDNSServices);
-const int kADBTransportServiceRefIndex = 0;
 
 #endif