Support OUT_DIR for license graph.

Bug: 226066987

Test: OUT_DIR=/tmp/outdir m all listshare checkshare htmlnotice rtrace dumpgraph dumpresolutions compliancenotice_bom compliancenotice_shippedlibs
Test: OUT_DIR=/tmp/outdir m /tmp/outdir/target/product/bonito/obj/NOTICE.xml.gz
Test: m all listshare checkshare htmlnotice rtrace dumpgraph dumpresolutions compliancenotice_bom compliancenotice_shippedlibs
Test: m out/target/product/bonito/obj/NOTICE.xml.gz

Change-Id: I6282c647a389c5935d5ce7c79193f86d32c76365
diff --git a/tools/compliance/cmd/rtrace/rtrace.go b/tools/compliance/cmd/rtrace/rtrace.go
index 7c63979..91171c4 100644
--- a/tools/compliance/cmd/rtrace/rtrace.go
+++ b/tools/compliance/cmd/rtrace/rtrace.go
@@ -18,6 +18,7 @@
 	"flag"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sort"
@@ -107,7 +108,7 @@
 		sources:         *sources,
 		stripPrefix:     *stripPrefix,
 	}
-	_, err := traceRestricted(ctx, os.Stdout, os.Stderr, flag.Args()...)
+	_, err := traceRestricted(ctx, os.Stdout, os.Stderr, compliance.FS, flag.Args()...)
 	if err != nil {
 		if err == failNoneRequested {
 			flag.Usage()
@@ -119,7 +120,7 @@
 }
 
 // traceRestricted implements the rtrace utility.
-func traceRestricted(ctx *context, stdout, stderr io.Writer, files ...string) (*compliance.LicenseGraph, error) {
+func traceRestricted(ctx *context, stdout, stderr io.Writer, rootFS fs.FS, files ...string) (*compliance.LicenseGraph, error) {
 	if len(files) < 1 {
 		return nil, failNoneRequested
 	}
@@ -129,7 +130,7 @@
 	}
 
 	// Read the license graph from the license metadata files (*.meta_lic).
-	licenseGraph, err := compliance.ReadLicenseGraph(os.DirFS("."), stderr, files)
+	licenseGraph, err := compliance.ReadLicenseGraph(rootFS, stderr, files)
 	if err != nil {
 		return nil, fmt.Errorf("Unable to read license metadata file(s) %q: %v\n", files, err)
 	}