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

webrtc/base/sslconfig.h

Index: webrtc/base/sslconfig.h
diff --git a/webrtc/base/sslconfig.h b/webrtc/base/sslconfig.h
new file mode 100644
index 0000000000000000000000000000000000000000..6aabad07a82555eaab7f38b5285b683a7e30a93c
--- /dev/null
+++ b/webrtc/base/sslconfig.h
@@ -0,0 +1,30 @@
+/*
+ *  Copyright 2012 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.
+ */
+
+#ifndef WEBRTC_BASE_SSLCONFIG_H_
+#define WEBRTC_BASE_SSLCONFIG_H_
+
+// If no preference has been indicated, default to SChannel on Windows and
+// OpenSSL everywhere else, if it is available.
+#if !defined(SSL_USE_SCHANNEL) && !defined(SSL_USE_OPENSSL)
+#if defined(WEBRTC_WIN)
+
+#define SSL_USE_SCHANNEL 1
+
+#else  // defined(WEBRTC_WIN)
+
+#if defined(HAVE_OPENSSL_SSL_H)
+#define SSL_USE_OPENSSL 1
+#endif
+
+#endif  // !defined(WEBRTC_WIN)
+#endif
+
+#endif  // WEBRTC_BASE_SSLCONFIG_H_