Move the caching/restoring code from soong to blueprint to fully skip build actions.

Bug: 358425833
Test: Manually verified the generated ninja and mk files and CI.
Change-Id: Ieebb822c46f37c0ff55fad08531e9870a76cbd7b
diff --git a/android/packaging.go b/android/packaging.go
index 42009d5..6bc1c74 100644
--- a/android/packaging.go
+++ b/android/packaging.go
@@ -15,6 +15,9 @@
 package android
 
 import (
+	"bytes"
+	"encoding/gob"
+	"errors"
 	"fmt"
 	"path/filepath"
 	"sort"
@@ -58,6 +61,36 @@
 	archType ArchType
 }
 
+func (p *PackagingSpec) GobEncode() ([]byte, error) {
+	w := new(bytes.Buffer)
+	encoder := gob.NewEncoder(w)
+	err := errors.Join(encoder.Encode(p.relPathInPackage), encoder.Encode(p.srcPath),
+		encoder.Encode(p.symlinkTarget), encoder.Encode(p.executable),
+		encoder.Encode(p.effectiveLicenseFiles), encoder.Encode(p.partition),
+		encoder.Encode(p.skipInstall), encoder.Encode(p.aconfigPaths),
+		encoder.Encode(p.archType))
+	if err != nil {
+		return nil, err
+	}
+
+	return w.Bytes(), nil
+}
+
+func (p *PackagingSpec) GobDecode(data []byte) error {
+	r := bytes.NewBuffer(data)
+	decoder := gob.NewDecoder(r)
+	err := errors.Join(decoder.Decode(&p.relPathInPackage), decoder.Decode(&p.srcPath),
+		decoder.Decode(&p.symlinkTarget), decoder.Decode(&p.executable),
+		decoder.Decode(&p.effectiveLicenseFiles), decoder.Decode(&p.partition),
+		decoder.Decode(&p.skipInstall), decoder.Decode(&p.aconfigPaths),
+		decoder.Decode(&p.archType))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (p *PackagingSpec) Equals(other *PackagingSpec) bool {
 	if other == nil {
 		return false