Remove unused Module.visibility() method

Bug: 155787200
Test: m nothing
Change-Id: Iee7a9ab9d816ed1948e2c7cde23f9907cfda337d

android/module.go

@@ -257,9 +257,6 @@ type Module interface {
 	// Get information about the properties that can contain visibility rules.
 	visibilityProperties() []visibilityProperty
 
-	// Get the visibility rules that control the visibility of this module.
-	visibility() []string
-
 	RequiredModuleNames() []string
 	HostRequiredModuleNames() []string
 	TargetRequiredModuleNames() []string
@@ -809,15 +806,6 @@ func (m *ModuleBase) visibilityProperties() []visibilityProperty {
 	return m.visibilityPropertyInfo
 }
 
-func (m *ModuleBase) visibility() []string {
-	// The soong_namespace module does not initialize the primaryVisibilityProperty.
-	if m.primaryVisibilityProperty != nil {
-		return m.primaryVisibilityProperty.getStrings()
-	} else {
-		return nil
-	}
-}
-
 func (m *ModuleBase) Target() Target {
 	return m.commonProperties.CompileTarget
 }