Allow pre-singleton types to be registered in RegistrationContext

Bug: 181070625
Test: m droid
Change-Id: I708b78ed0b42ec55b0442307f40531cfe1233c2b
diff --git a/android/register.go b/android/register.go
index 18c743f..47df972 100644
--- a/android/register.go
+++ b/android/register.go
@@ -168,6 +168,7 @@
 type RegistrationContext interface {
 	RegisterModuleType(name string, factory ModuleFactory)
 	RegisterSingletonModuleType(name string, factory SingletonModuleFactory)
+	RegisterPreSingletonType(name string, factory SingletonFactory)
 	RegisterSingletonType(name string, factory SingletonFactory)
 	PreArchMutators(f RegisterMutatorFunc)
 
@@ -208,6 +209,7 @@
 type initRegistrationContext struct {
 	moduleTypes        map[string]ModuleFactory
 	singletonTypes     map[string]SingletonFactory
+	preSingletonTypes  map[string]SingletonFactory
 	moduleTypesForDocs map[string]reflect.Value
 }
 
@@ -238,6 +240,14 @@
 	RegisterSingletonType(name, factory)
 }
 
+func (ctx *initRegistrationContext) RegisterPreSingletonType(name string, factory SingletonFactory) {
+	if _, present := ctx.preSingletonTypes[name]; present {
+		panic(fmt.Sprintf("pre singleton type %q is already registered", name))
+	}
+	ctx.preSingletonTypes[name] = factory
+	RegisterPreSingletonType(name, factory)
+}
+
 func (ctx *initRegistrationContext) PreArchMutators(f RegisterMutatorFunc) {
 	PreArchMutators(f)
 }