libbinderwrapper: Add GetCallingUid() and GetCallingPid().

Add methods to BinderWrapper for getting the caller's UID
and PID while in a transaction.

Bug: 24988639
Change-Id: Ibd711fc6b3d83623d4bb1060838c65aaef30d76e
diff --git a/libbinderwrapper/real_binder_wrapper.h b/libbinderwrapper/real_binder_wrapper.h
index 8e281f2..ea08371 100644
--- a/libbinderwrapper/real_binder_wrapper.h
+++ b/libbinderwrapper/real_binder_wrapper.h
@@ -38,6 +38,8 @@
   bool RegisterForDeathNotifications(const sp<IBinder>& binder,
                                      const base::Closure& callback) override;
   bool UnregisterForDeathNotifications(const sp<IBinder>& binder) override;
+  uid_t GetCallingUid() override;
+  pid_t GetCallingPid() override;
 
  private:
   class DeathRecipient;