adb: split daemon services out of service_to_fd.

Let minadbd override daemon services by pulling out the daemon services
into a separate translation unit, that isn't compiled into libadbd.

Bug: http://b/111831478
Test: mma
Change-Id: Iecfebea371e03864108eca9a4d2e9cfd5db34749
diff --git a/adb/services.h b/adb/services.h
index 0428ca4..0ce25ba 100644
--- a/adb/services.h
+++ b/adb/services.h
@@ -17,8 +17,11 @@
 #ifndef SERVICES_H_
 #define SERVICES_H_
 
+#include "adb_unique_fd.h"
+
 constexpr char kShellServiceArgRaw[] = "raw";
 constexpr char kShellServiceArgPty[] = "pty";
 constexpr char kShellServiceArgShellProtocol[] = "v2";
 
+unique_fd create_service_thread(const char* service_name, std::function<void(unique_fd)> func);
 #endif  // SERVICES_H_