Allow AIBinder<->IBinder when sharing libbinder.

Fixes: 159372351
Test: libbinder_ndk_unit_test
Change-Id: I4051e32e487e92ee70f85a733877cd709fc510eb
diff --git a/libs/binder/ndk/ibinder.cpp b/libs/binder/ndk/ibinder.cpp
index 7540cae..d287290 100644
--- a/libs/binder/ndk/ibinder.cpp
+++ b/libs/binder/ndk/ibinder.cpp
@@ -698,3 +698,14 @@
 const char* AIBinder_getCallingSid() {
     return ::android::IPCThreadState::self()->getCallingSid();
 }
+
+android::sp<android::IBinder> AIBinder_toPlatformBinder(AIBinder* binder) {
+    if (binder == nullptr) return nullptr;
+    return binder->getBinder();
+}
+
+AIBinder* AIBinder_fromPlatformBinder(const android::sp<android::IBinder>& binder) {
+    sp<AIBinder> ndkBinder = ABpBinder::lookupOrCreateFromBinder(binder);
+    AIBinder_incStrong(ndkBinder.get());
+    return ndkBinder.get();
+}