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

webrtc/base/sslidentity.cc

Index: webrtc/base/sslidentity.cc
diff --git a/webrtc/base/sslidentity.cc b/webrtc/base/sslidentity.cc
index a5dd7b9ce686b63256fe417836c936e6e2116e59..645050a7e4b9deccc0b045d4539c6a2cc5f35b93 100644
--- a/webrtc/base/sslidentity.cc
+++ b/webrtc/base/sslidentity.cc
@@ -17,8 +17,14 @@
 #include "webrtc/base/base64.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
+#include "webrtc/base/sslconfig.h"
+#include "webrtc/base/sslfingerprint.h"
+
+#if SSL_USE_OPENSSL
+
 #include "webrtc/base/opensslidentity.h"
-#include "webrtc/base/sslfingerprint.h"
+
+#endif  // SSL_USE_OPENSSL
 
 namespace rtc {
 
@@ -207,6 +213,8 @@
   std::for_each(certs_.begin(), certs_.end(), DeleteCert);
 }
 
+#if SSL_USE_OPENSSL
+
 // static
 SSLCertificate* SSLCertificate::FromPEMString(const std::string& pem_string) {
   return OpenSSLCertificate::FromPEMString(pem_string);
@@ -251,6 +259,12 @@
 bool operator!=(const SSLIdentity& a, const SSLIdentity& b) {
   return !(a == b);
 }
+
+#else  // !SSL_USE_OPENSSL
+
+#error "No SSL implementation"
+
+#endif  // SSL_USE_OPENSSL
 
 // Read |n| bytes from ASN1 number string at *|pp| and return the numeric value.
 // Update *|pp| and *|np| to reflect number of read bytes.