Add exported_systemserverclasspath_fragments to prebuilt_apex rule.

This is for exporting the contents of systemserverclasspath_fragment for
dexpreopting.

Bug: 194150908
Test: manual - 1. Patch aosp/1818020 and aosp/1834534
  2. m SOONG_CONFIG_art_module_source_build=false com.android.art
Change-Id: I7d2d2e02869d8a523f7c0efbbff81706672a95c5
diff --git a/java/systemserver_classpath_fragment.go b/java/systemserver_classpath_fragment.go
index e2738d7..26796a6 100644
--- a/java/systemserver_classpath_fragment.go
+++ b/java/systemserver_classpath_fragment.go
@@ -133,8 +133,12 @@
 // they were listed in java_libs.
 func (systemServerClasspathFragmentContentDependencyTag) CopyDirectlyInAnyApex() {}
 
+// Contents of system server fragments require files from prebuilt apex files.
+func (systemServerClasspathFragmentContentDependencyTag) RequiresFilesFromPrebuiltApex() {}
+
 var _ android.ReplaceSourceWithPrebuilt = systemServerClasspathFragmentContentDepTag
 var _ android.CopyDirectlyInAnyApexTag = systemServerClasspathFragmentContentDepTag
+var _ android.RequiresFilesFromPrebuiltApexTag = systemServerClasspathFragmentContentDepTag
 
 // The tag used for the dependency between the systemserverclasspath_fragment module and its contents.
 var systemServerClasspathFragmentContentDepTag = systemServerClasspathFragmentContentDependencyTag{}
@@ -177,6 +181,12 @@
 	return module.prebuilt.Name(module.ModuleBase.Name())
 }
 
+func (module *prebuiltSystemServerClasspathModule) RequiredFilesFromPrebuiltApex(ctx android.BaseModuleContext) []string {
+	return nil
+}
+
+var _ android.RequiredFilesFromPrebuiltApex = (*prebuiltSystemServerClasspathModule)(nil)
+
 func prebuiltSystemServerClasspathModuleFactory() android.Module {
 	m := &prebuiltSystemServerClasspathModule{}
 	m.AddProperties(&m.properties)