Prepare for a type-safe OnceKey

Add an opaque OnceKey type and use it for all calls to Once in
build/soong.  A future patch will convert the arguments to
Once* to OnceKey once users outside build/soong have been updated.

Test: onceper_test.go
Change-Id: Ifcb338e6e603e804e507203c9508d30ffb2df966

1 files changed, 1 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
index 5e9c600b..591e5c85 100644
--- a/Android.bp
+++ b/Android.bp
@@ -78,6 +78,7 @@ bootstrap_go_package {
         "android/expand_test.go",
         "android/namespace_test.go",
         "android/neverallow_test.go",
+        "android/onceper_test.go",
         "android/paths_test.go",
         "android/prebuilt_test.go",
         "android/prebuilt_etc_test.go",