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

webrtc/base/opensslidentity.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  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"
 
 #include <memory>
 
 // Must be included first before openssl headers.
 #include "webrtc/base/win32.h"  // NOLINT
 
 #include <openssl/bio.h>
 #include <openssl/err.h>
 #include <openssl/pem.h>
@@ skipping 546 matching lines @@
 bool OpenSSLIdentity::operator==(const OpenSSLIdentity& other) const {
   return *this->key_pair_ == *other.key_pair_ &&
          *this->certificate_ == *other.certificate_;
 }
 
 bool OpenSSLIdentity::operator!=(const OpenSSLIdentity& other) const {
   return !(*this == other);
 }
 
 }  // namespace rtc
+
+#endif  // HAVE_OPENSSL_SSL_H