Share EffectiveLicenseFiles for snapshot modules

License files must be captured with the snapshot modules. NoticeFiles
does not have the information provided by the `license` module.
Reading the `Effective_license_text`, snapshot includes the required
license files.

Bug: 190690041
Test: build
      check the NOTICE files built from snapshots
Change-Id: I96c4579b4bef484cbb39fc06c707742a02a2b90b

android/module.go

@@ -473,6 +473,7 @@ type Module interface {
 	InitRc() Paths
 	VintfFragments() Paths
 	NoticeFiles() Paths
+	EffectiveLicenseFiles() Paths
 
 	AddProperties(props ...interface{})
 	GetProperties() []interface{}
@@ -1505,6 +1506,10 @@ func (m *ModuleBase) ExportedToMake() bool {
 	return m.commonProperties.NamespaceExportedToMake
 }
 
+func (m *ModuleBase) EffectiveLicenseFiles() Paths {
+	return m.commonProperties.Effective_license_text
+}
+
 // computeInstallDeps finds the installed paths of all dependencies that have a dependency
 // tag that is annotated as needing installation via the IsInstallDepNeeded method.
 func (m *ModuleBase) computeInstallDeps(ctx ModuleContext) ([]*installPathsDepSet, []*packagingSpecsDepSet) {