Add MutatorName to mutator contexts

Follow https://github.com/google/blueprint/pull/255.

Bug: 136473661
Test: m checkbuild
Change-Id: Ia74d442c925689fa1e06a70c2acfed925063f844
diff --git a/android/mutator.go b/android/mutator.go
index 070b420..d288194 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -117,6 +117,8 @@
 type TopDownMutatorContext interface {
 	BaseModuleContext
 
+	MutatorName() string
+
 	Rename(name string)
 
 	CreateModule(blueprint.ModuleFactory, ...interface{})
@@ -132,6 +134,8 @@
 type BottomUpMutatorContext interface {
 	BaseModuleContext
 
+	MutatorName() string
+
 	Rename(name string)
 
 	AddDependency(module blueprint.Module, tag blueprint.DependencyTag, name ...string)
@@ -229,6 +233,10 @@
 // non-overridden method has to be forwarded.  There are fewer non-overridden methods, so use the latter.  The following
 // methods forward to the identical blueprint versions for topDownMutatorContext and bottomUpMutatorContext.
 
+func (t *topDownMutatorContext) MutatorName() string {
+	return t.bp.MutatorName()
+}
+
 func (t *topDownMutatorContext) Rename(name string) {
 	t.bp.Rename(name)
 }
@@ -237,6 +245,10 @@
 	t.bp.CreateModule(factory, props...)
 }
 
+func (b *bottomUpMutatorContext) MutatorName() string {
+	return b.bp.MutatorName()
+}
+
 func (b *bottomUpMutatorContext) Rename(name string) {
 	b.bp.Rename(name)
 }