libbinder_ndk: AIBinder_{setRequesting,getCalling}Sid

This adds the following two methods for APEX:
- AIBinder_setRequestingSid
- AIBinder_getCallingSid

This is not made as an SDK API because security contexts are a platform
detail, and the platform header is shared for APEX and platform use
(different from parcel for now).

Fixes: 159135973
Test: libbinder_ndk_unit_test
Change-Id: Iec64577ebbb7a8cc6550d1d211fe5f562337cf0b
diff --git a/libs/binder/include/binder/IPCThreadState.h b/libs/binder/include/binder/IPCThreadState.h
index b4e4a42..8d51cdc 100644
--- a/libs/binder/include/binder/IPCThreadState.h
+++ b/libs/binder/include/binder/IPCThreadState.h
@@ -50,7 +50,7 @@
              * Returns the SELinux security identifier of the process which has
              * made the current binder call. If not in a binder call this will
              * return nullptr. If this isn't requested with
-             * IBinder::setRequestingSid, it will also return nullptr.
+             * Binder::setRequestingSid, it will also return nullptr.
              *
              * This can't be restored once it's cleared, and it does not return the
              * context of the current process when not in a binder call.