Extract sdk registration code into function for reuse

Test: m nothing
Change-Id: I0d0e36324808831deb9a32f07ca3696125703873
diff --git a/sdk/exports.go b/sdk/exports.go
index d313057..9a0ba4e 100644
--- a/sdk/exports.go
+++ b/sdk/exports.go
@@ -17,8 +17,12 @@
 import "android/soong/android"
 
 func init() {
-	android.RegisterModuleType("module_exports", ModuleExportsFactory)
-	android.RegisterModuleType("module_exports_snapshot", ModuleExportsSnapshotsFactory)
+	registerModuleExportsBuildComponents(android.InitRegistrationContext)
+}
+
+func registerModuleExportsBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("module_exports", ModuleExportsFactory)
+	ctx.RegisterModuleType("module_exports_snapshot", ModuleExportsSnapshotsFactory)
 }
 
 // module_exports defines the exports of a mainline module. The exports are Soong modules