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

webrtc/api/test/peerconnectiontestwrapper.cc

Index: webrtc/api/test/peerconnectiontestwrapper.cc
diff --git a/webrtc/api/test/peerconnectiontestwrapper.cc b/webrtc/api/test/peerconnectiontestwrapper.cc
index 3254480a27f409239945d3f4be9e0ed76f907b46..b1eb58677d310e47461d5fd833fe2a1f436952c1 100644
--- a/webrtc/api/test/peerconnectiontestwrapper.cc
+++ b/webrtc/api/test/peerconnectiontestwrapper.cc
@@ -76,7 +76,8 @@
   }
 
   std::unique_ptr<rtc::RTCCertificateGeneratorInterface> cert_generator(
-      new FakeRTCCertificateGenerator());
+      rtc::SSLStreamAdapter::HaveDtlsSrtp() ? new FakeRTCCertificateGenerator()
+                                            : nullptr);
   peer_connection_ = peer_connection_factory_->CreatePeerConnection(
       config, constraints, std::move(port_allocator), std::move(cert_generator),
       this);