Define an output file of runtime_resource_overlay

So that rros can be data of test modules.

Test: go test
Change-Id: I460a97fd9f430ec8e52ef6756d74b02693469d06
diff --git a/java/rro.go b/java/rro.go
index 42d42b8..4ae8d7f 100644
--- a/java/rro.go
+++ b/java/rro.go
@@ -99,15 +99,6 @@
 	Overrides []string
 }
 
-// RuntimeResourceOverlayModule interface is used by the apex package to gather information from
-// a RuntimeResourceOverlay module.
-type RuntimeResourceOverlayModule interface {
-	android.Module
-	OutputFile() android.Path
-	Certificate() Certificate
-	Theme() string
-}
-
 // RRO's partition logic is different from the partition logic of other modules defined in soong/android/paths.go
 // The default partition for RRO is "/product" and not "/system"
 func rroPartition(ctx android.ModuleContext) string {
@@ -217,11 +208,13 @@
 	})
 
 	android.SetProvider(ctx, RuntimeResourceOverlayInfoProvider, RuntimeResourceOverlayInfo{
-		OutputFile:  r.OutputFile(),
+		OutputFile:  r.outputFile,
 		Certificate: r.Certificate(),
 		Theme:       r.Theme(),
 	})
 
+	ctx.SetOutputFiles([]android.Path{r.outputFile}, "")
+
 	buildComplianceMetadata(ctx)
 }
 
@@ -252,10 +245,6 @@
 	return r.certificate
 }
 
-func (r *RuntimeResourceOverlay) OutputFile() android.Path {
-	return r.outputFile
-}
-
 func (r *RuntimeResourceOverlay) Theme() string {
 	return String(r.properties.Theme)
 }