Remove pre singletons

They're no longer used.

Test: m nothing --no-skip-soong-tests
Change-Id: I8984164cfc1a062c428ea7f1a4dd5b8940bee84b
diff --git a/android/register.go b/android/register.go
index 6182159..de31353 100644
--- a/android/register.go
+++ b/android/register.go
@@ -22,6 +22,7 @@
 	"regexp"
 
 	"android/soong/shared"
+
 	"github.com/google/blueprint"
 )
 
@@ -66,9 +67,6 @@
 var moduleTypeByFactory = map[reflect.Value]string{}
 
 type singleton struct {
-	// True if this should be registered as a pre-singleton, false otherwise.
-	pre bool
-
 	// True if this should be registered as a parallel singleton.
 	parallel bool
 
@@ -77,11 +75,7 @@
 }
 
 func newSingleton(name string, factory SingletonFactory, parallel bool) singleton {
-	return singleton{pre: false, parallel: parallel, name: name, factory: factory}
-}
-
-func newPreSingleton(name string, factory SingletonFactory) singleton {
-	return singleton{pre: true, parallel: false, name: name, factory: factory}
+	return singleton{parallel: parallel, name: name, factory: factory}
 }
 
 func (s singleton) componentName() string {
@@ -90,17 +84,12 @@
 
 func (s singleton) register(ctx *Context) {
 	adaptor := SingletonFactoryAdaptor(ctx, s.factory)
-	if s.pre {
-		ctx.RegisterPreSingletonType(s.name, adaptor)
-	} else {
-		ctx.RegisterSingletonType(s.name, adaptor, s.parallel)
-	}
+	ctx.RegisterSingletonType(s.name, adaptor, s.parallel)
 }
 
 var _ sortableComponent = singleton{}
 
 var singletons sortableComponents
-var preSingletons sortableComponents
 
 type mutator struct {
 	name              string
@@ -164,10 +153,6 @@
 	registerSingletonType(name, factory, true)
 }
 
-func RegisterPreSingletonType(name string, factory SingletonFactory) {
-	preSingletons = append(preSingletons, newPreSingleton(name, factory))
-}
-
 type Context struct {
 	*blueprint.Context
 	config Config
@@ -253,8 +238,6 @@
 // Register the pipeline of singletons, module types, and mutators for
 // generating build.ninja and other files for Kati, from Android.bp files.
 func (ctx *Context) Register() {
-	preSingletons.registerAll(ctx)
-
 	for _, t := range moduleTypes {
 		t.register(ctx)
 	}
@@ -277,17 +260,17 @@
 func collateGloballyRegisteredSingletons() sortableComponents {
 	allSingletons := append(sortableComponents(nil), singletons...)
 	allSingletons = append(allSingletons,
-		singleton{pre: false, parallel: true, name: "bazeldeps", factory: BazelSingleton},
+		singleton{parallel: true, name: "bazeldeps", factory: BazelSingleton},
 
 		// Register phony just before makevars so it can write out its phony rules as Make rules
-		singleton{pre: false, parallel: false, name: "phony", factory: phonySingletonFactory},
+		singleton{parallel: false, name: "phony", factory: phonySingletonFactory},
 
 		// Register makevars after other singletons so they can export values through makevars
-		singleton{pre: false, parallel: false, name: "makevars", factory: makeVarsSingletonFunc},
+		singleton{parallel: false, name: "makevars", factory: makeVarsSingletonFunc},
 
 		// Register env and ninjadeps last so that they can track all used environment variables and
 		// Ninja file dependencies stored in the config.
-		singleton{pre: false, parallel: false, name: "ninjadeps", factory: ninjaDepsSingletonFactory},
+		singleton{parallel: false, name: "ninjadeps", factory: ninjaDepsSingletonFactory},
 	)
 
 	return allSingletons
@@ -317,7 +300,6 @@
 	RegisterModuleType(name string, factory ModuleFactory)
 	RegisterSingletonModuleType(name string, factory SingletonModuleFactory)
 	RegisterParallelSingletonModuleType(name string, factory SingletonModuleFactory)
-	RegisterPreSingletonType(name string, factory SingletonFactory)
 	RegisterParallelSingletonType(name string, factory SingletonFactory)
 	RegisterSingletonType(name string, factory SingletonFactory)
 	PreArchMutators(f RegisterMutatorFunc)
@@ -349,9 +331,8 @@
 //	ctx := android.NewTestContext(config)
 //	RegisterBuildComponents(ctx)
 var InitRegistrationContext RegistrationContext = &initRegistrationContext{
-	moduleTypes:       make(map[string]ModuleFactory),
-	singletonTypes:    make(map[string]SingletonFactory),
-	preSingletonTypes: make(map[string]SingletonFactory),
+	moduleTypes:    make(map[string]ModuleFactory),
+	singletonTypes: make(map[string]SingletonFactory),
 }
 
 // Make sure the TestContext implements RegistrationContext.
@@ -360,7 +341,6 @@
 type initRegistrationContext struct {
 	moduleTypes        map[string]ModuleFactory
 	singletonTypes     map[string]SingletonFactory
-	preSingletonTypes  map[string]SingletonFactory
 	moduleTypesForDocs map[string]reflect.Value
 }
 
@@ -406,14 +386,6 @@
 	ctx.registerSingletonType(name, factory, true)
 }
 
-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)
 }