bootclasspath_fragment: Add hidden API flag files to snapshot

These are needed at the moment to ensure the hidden API processing
generates the same set of flags whether it is being generated from
source or prebuilts. Soon these will be needed to ensure that the
hidden API flags generated for the individual modules are compatible
with previous releases.

Bug: 179354495
Test: m art-module-sdk and check snapshot zip contains the files
      and the generated Android.bp references them.
Change-Id: I9a3334cc48faa381bbbcbbb59479db719042796a

java/boot_image.go

@@ -16,6 +16,7 @@ package java
 
 import (
 	"fmt"
+	"path/filepath"
 	"strings"
 
 	"android/soong/android"
@@ -324,6 +325,9 @@ type bootImageSdkMemberProperties struct {
 
 	// Contents of the bootclasspath fragment
 	Contents []string
+
+	// Flag files by *hiddenAPIFlagFileCategory
+	Flag_files_by_category map[*hiddenAPIFlagFileCategory]android.Paths
 }
 
 func (b *bootImageSdkMemberProperties) PopulateFromVariant(ctx android.SdkMemberContext, variant android.Module) {
@@ -336,6 +340,11 @@ func (b *bootImageSdkMemberProperties) PopulateFromVariant(ctx android.SdkMember
 		// boot image. Therefore, contents property is only copied if the image name is not specified.
 		b.Contents = module.properties.Contents
 	}
+
+	// Get the flag file information from the module.
+	mctx := ctx.SdkModuleContext()
+	flagFileInfo := mctx.OtherModuleProvider(module, hiddenAPIFlagFileInfoProvider).(hiddenAPIFlagFileInfo)
+	b.Flag_files_by_category = flagFileInfo.categoryToPaths
 }
 
 func (b *bootImageSdkMemberProperties) AddToPropertySet(ctx android.SdkMemberContext, propertySet android.BpPropertySet) {
@@ -346,6 +355,23 @@ func (b *bootImageSdkMemberProperties) AddToPropertySet(ctx android.SdkMemberCon
 	if len(b.Contents) > 0 {
 		propertySet.AddPropertyWithTag("contents", b.Contents, ctx.SnapshotBuilder().SdkMemberReferencePropertyTag(true))
 	}
+
+	builder := ctx.SnapshotBuilder()
+	if b.Flag_files_by_category != nil {
+		hiddenAPISet := propertySet.AddPropertySet("hidden_api")
+		for _, category := range hiddenAPIFlagFileCategories {
+			paths := b.Flag_files_by_category[category]
+			if len(paths) > 0 {
+				dests := []string{}
+				for _, p := range paths {
+					dest := filepath.Join("hiddenapi", p.Base())
+					builder.CopyToSnapshot(p, dest)
+					dests = append(dests, dest)
+				}
+				hiddenAPISet.AddProperty(category.propertyName, dests)
+			}
+		}
+	}
 }
 
 var _ android.SdkMemberType = (*bootImageMemberType)(nil)