Expose android.filesToInstall

It will be used by the cvd_host_package module type to gather installed
files and package them in a distributable format.

Bug: 168086242
Test: m

Change-Id: I3af6dcda0bce1f298b1500fbac311c9593ddf375
diff --git a/android/module.go b/android/module.go
index c4e43c2..303e98c 100644
--- a/android/module.go
+++ b/android/module.go
@@ -435,7 +435,7 @@
 	HostRequiredModuleNames() []string
 	TargetRequiredModuleNames() []string
 
-	filesToInstall() InstallPaths
+	FilesToInstall() InstallPaths
 }
 
 // Qualified id for a module
@@ -1241,14 +1241,14 @@
 	// TODO(ccross): we need to use WalkDeps and have some way to know which dependencies require installation
 	ctx.VisitDepsDepthFirst(func(m blueprint.Module) {
 		if a, ok := m.(Module); ok {
-			result = append(result, a.filesToInstall()...)
+			result = append(result, a.FilesToInstall()...)
 		}
 	})
 
 	return result
 }
 
-func (m *ModuleBase) filesToInstall() InstallPaths {
+func (m *ModuleBase) FilesToInstall() InstallPaths {
 	return m.installFiles
 }