Remove exportable modules when generating snapshots targeting older platform

This change modifies the contents of the generated Android.bp files so
that when generating a snapshot on a older platform, the "exportable"
modules are removed from the bp files, as the "exportable" modules are
first introduced in V and do not exist in older platforms.

Bug: 345162614
Test: ABTD
Change-Id: I2dba51b98deec7805bd796647a66981f237c55a9

sdk/update.go

@@ -480,6 +480,12 @@ be unnecessary as every module in the sdk already has its own licenses property.
 		// Transform the module module to make it suitable for use in the snapshot.
 		module = transformModule(module, snapshotTransformer)
 		module = transformModule(module, emptyClasspathContentsTransformation{})
+
+		targetApiLevel, err := android.ApiLevelFromUserWithConfig(ctx.Config(), s.targetBuildRelease(ctx).name)
+		if err == nil && targetApiLevel.LessThan(android.ApiLevelVanillaIceCream) {
+			module = transformModule(module, replaceExportablePropertiesTransformer{})
+		}
+
 		if module != nil {
 			bpFile.AddModule(module)
 		}
@@ -804,6 +810,50 @@ func (t pruneEmptySetTransformer) transformPropertySetAfterContents(_ string, pr
 	}
 }
 
+type replaceExportablePropertiesTransformer struct {
+	identityTransformation
+}
+
+var _ bpTransformer = (*replaceExportablePropertiesTransformer)(nil)
+
+func handleExportableProperties[T any](value T) any {
+	switch v := any(value).(type) {
+	case string:
+		return java.AllApiScopes.ConvertStubsLibraryExportableToEverything(v)
+	case *bpPropertySet:
+		v.properties = handleExportableProperties(v.properties).(map[string]interface{})
+		return v
+	case []string:
+		result := make([]string, len(v))
+		for i, elem := range v {
+			result[i] = handleExportableProperties(elem).(string)
+		}
+		return result
+	case []any:
+		result := make([]any, len(v))
+		for i, elem := range v {
+			result[i] = handleExportableProperties(elem)
+		}
+		return result
+	case map[string]any:
+		result := make(map[string]any)
+		for k, val := range v {
+			result[k] = handleExportableProperties(val)
+		}
+		return result
+	default:
+		return value
+	}
+}
+
+func (t replaceExportablePropertiesTransformer) transformPropertySetAfterContents(name string, propertySet *bpPropertySet, tag android.BpPropertyTag) (*bpPropertySet, android.BpPropertyTag) {
+	if name == "name" {
+		return propertySet, tag
+	}
+	propertySet.properties = handleExportableProperties(propertySet.properties).(map[string]interface{})
+	return propertySet, tag
+}
+
 func generateBpContents(bpFile *bpFile) string {
 	contents := &generatedContents{}
 	contents.IndentedPrintf("// This is auto-generated. DO NOT EDIT.\n")