IGL | shell | netservice | remove hack to prevent stripping

Summary: Use attribute instead of Obj-C to prevent dead-strip removal

Reviewed By: EricGriffith, MichaelTay

Differential Revision: D62417120

fbshipit-source-id: 2711fd64b8a504a6fb0b3ff89f6704a2dc39c82e

shell/shared/netservice/apple/NetServiceExtensionApple.mm

@@ -110,19 +110,9 @@ - (void)netServiceBrowser:(NSNetServiceBrowser*)browser
   }
 }
 
-IGL_API IGLShellExtension* IGLShellExtension_NewIglShellNetService() {
+IGL_API __attribute((retain, used)) IGLShellExtension* IGLShellExtension_NewIglShellNetService() {
   auto* extension = new NetServiceExtensionApple;
   return static_cast<IGLShellExtension*>(extension);
 }
 
 } // namespace igl::shell::netservice
-
-// TODO: Find better way to prevent stripping
-@interface IglShellApple_NetServiceExtension : NSObject
-@end
-
-@implementation IglShellApple_NetServiceExtension
-+ (IGLShellExtension_NewCFunction)cFunc {
-  return igl::shell::netservice::IGLShellExtension_NewIglShellNetService;
-}
-@end