Revert of Removing #defines previously used for building without BoringSSL/OpenSSL.

webrtc/base/openssldigest.cc

Index: webrtc/base/openssldigest.cc
diff --git a/webrtc/base/openssldigest.cc b/webrtc/base/openssldigest.cc
index 0413f8f41055c720f28f099e2b90b77fc90905b3..2618b7f9fd2ec1a8025bd33f3ef53452f8eb9c28 100644
--- a/webrtc/base/openssldigest.cc
+++ b/webrtc/base/openssldigest.cc
@@ -7,6 +7,8 @@
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
+
+#if HAVE_OPENSSL_SSL_H
 
 #include "webrtc/base/openssldigest.h"
 
@@ -116,3 +118,5 @@
 }
 
 }  // namespace rtc
+
+#endif  // HAVE_OPENSSL_SSL_H