Soong filesystem may install aconfig_flags.pb

By setting aconfig_flags: true, soong filesystem module installs the
aconfig_flags.pb file to its etc directory.

We need to define aconfigFilePaths to ModuleBase to store the list of
aconfig file paths that is generated from the GenerateBuildActions().
The aconfigFilePaths are collected when build the filesystem module
to build the aconfig_flags.pb for the filesystem image.

Bug: 335363964
Test: compare the cache list with those generated from make.
Change-Id: Ia32b566bf43174e94b9e610b9503608c6b583899
diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index b342ae9..d8a00e2 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -131,6 +131,9 @@
 	// Default is false
 	Build_logtags *bool
 
+	// Install aconfig_flags.pb file for the modules installed in this partition.
+	Gen_aconfig_flags_pb *bool
+
 	Fsverity fsverityProperties
 }
 
@@ -300,6 +303,7 @@
 	f.addMakeBuiltFiles(ctx, builder, rootDir)
 	f.buildFsverityMetadataFiles(ctx, builder, specs, rootDir, rebasedDir)
 	f.buildEventLogtagsFile(ctx, builder, rebasedDir)
+	f.buildAconfigFlagsFiles(ctx, builder, specs, rebasedDir)
 
 	// run host_init_verifier
 	// Ideally we should have a concept of pluggable linters that verify the generated image.
@@ -441,6 +445,7 @@
 	f.buildNonDepsFiles(ctx, builder, rootDir)
 	f.buildFsverityMetadataFiles(ctx, builder, specs, rootDir, rebasedDir)
 	f.buildEventLogtagsFile(ctx, builder, rebasedDir)
+	f.buildAconfigFlagsFiles(ctx, builder, specs, rebasedDir)
 
 	output := android.PathForModuleOut(ctx, f.installFileName()).OutputPath
 	cmd := builder.Command().