Test that servers enforce session timeouts.

Extend the DTLS mock clock to apply to sessions too and test that
resumption behaves as expected.

Change-Id: Ib8fdec91b36e11cfa032872b63cf589f93b3da13
Reviewed-on: https://boringssl-review.googlesource.com/9110
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/internal.h b/ssl/internal.h
index 5c8f32c..c69bc5f 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1479,6 +1479,8 @@
                             uint16_t signature_algorithm);
 void ssl_set_client_disabled(SSL *ssl);
 
+void ssl_get_current_time(const SSL *ssl, struct timeval *out_clock);
+
 
 #if defined(__cplusplus)
 } /* extern C */