make DoVerify protected

Bug: 21445004
Change-Id: Iac7967c72b4455813a043b24941f9bfd7bf8878e
diff --git a/include/gatekeeper/gatekeeper.h b/include/gatekeeper/gatekeeper.h
index e1950f6..7e1421f 100644
--- a/include/gatekeeper/gatekeeper.h
+++ b/include/gatekeeper/gatekeeper.h
@@ -164,6 +164,11 @@
      */
     virtual bool IsHardwareBacked() const = 0;
 
+    /**
+     * Verifies that handle matches password HMAC'ed with the password_key
+     */
+    virtual bool DoVerify(const password_handle_t *expected_handle, const SizedBuffer &password);
+
 private:
     /**
      * Generates a signed attestation of an authentication event and assings
@@ -175,11 +180,6 @@
             secure_id_t user_id, secure_id_t authenticator_id, uint64_t challenge);
 
     /**
-     * Verifies that handle matches password HMAC'ed with the password_key
-     */
-    bool DoVerify(const password_handle_t *expected_handle, const SizedBuffer &password);
-
-    /**
      * Populates password_handle with the data provided and computes HMAC.
      */
     bool CreatePasswordHandle(SizedBuffer *password_handle, salt_t salt,