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

webrtc/base/opensslidentity.cc

Index: webrtc/base/opensslidentity.cc
diff --git a/webrtc/base/opensslidentity.cc b/webrtc/base/opensslidentity.cc
index 7b96f6a20616b228db03bb07cb06b94934a5ffe2..2f1c565938cec00247b471a78fa84d437f1f7035 100644
--- a/webrtc/base/opensslidentity.cc
+++ b/webrtc/base/opensslidentity.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/opensslidentity.h"
 
@@ -574,3 +576,5 @@
 }
 
 }  // namespace rtc
+
+#endif  // HAVE_OPENSSL_SSL_H