Removal of unused methods AppendProperties and PrependProperties from topDownMutatorContext

Test: m nothing
Bug: n/a

Change-Id: Ia37d1c9b96c39603964ba8db2ea6ba52d1138472
diff --git a/android/module.go b/android/module.go
index 767f9f4..b500f01 100644
--- a/android/module.go
+++ b/android/module.go
@@ -1300,6 +1300,8 @@
 
 func (m *ModuleBase) DepsMutator(BottomUpMutatorContext) {}
 
+// AddProperties "registers" the provided props
+// each value in props MUST be a pointer to a struct
 func (m *ModuleBase) AddProperties(props ...interface{}) {
 	m.registerProps = append(m.registerProps, props...)
 }
diff --git a/android/mutator.go b/android/mutator.go
index 461cb17..0a93517 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -529,28 +529,6 @@
 	mod.base().addBp2buildInfo(info)
 }
 
-func (t *topDownMutatorContext) appendPrependHelper(props []interface{},
-	extendFn func([]interface{}, interface{}, proptools.ExtendPropertyFilterFunc) error) {
-	for _, p := range props {
-		err := extendFn(t.Module().base().customizableProperties, p, nil)
-		if err != nil {
-			if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
-				t.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
-			} else {
-				panic(err)
-			}
-		}
-	}
-}
-
-func (t *topDownMutatorContext) AppendProperties(props ...interface{}) {
-	t.appendPrependHelper(props, proptools.AppendMatchingProperties)
-}
-
-func (t *topDownMutatorContext) PrependProperties(props ...interface{}) {
-	t.appendPrependHelper(props, proptools.PrependMatchingProperties)
-}
-
 // android.topDownMutatorContext either has to embed blueprint.TopDownMutatorContext, in which case every method that
 // has an overridden version in android.BaseModuleContext has to be manually forwarded to BaseModuleContext to avoid
 // ambiguous method errors, or it has to store a blueprint.TopDownMutatorContext non-embedded, in which case every