Revert of Removing #defines previously used for building without BoringSSL/OpenSSL. (patchset #2 id:20001 of https://codereview.webrtc.org/2640513002/ )

Reason for revert:
Broke chromium build, due to a config being removed. Will add it back and remove the dependency in a chromium CL.

Original issue's description:
> Removing #defines previously used for building without BoringSSL/OpenSSL.
>
> These defines don't work any more, so they only cause confusion:
>
> FEATURE_ENABLE_SSL
> HAVE_OPENSSL_SSL_H
> SSL_USE_OPENSSL
>
> BUG=webrtc:7025
>
> Review-Url: https://codereview.webrtc.org/2640513002
> Cr-Commit-Position: refs/heads/master@{#16196}
> Committed: https://chromium.googlesource.com/external/webrtc/+/eaa826c2ee0668cfb4a0dfb66f8d388b65da20f5

TBR=kjellander@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7025

Review-Url: https://codereview.webrtc.org/2648003003
Cr-Commit-Position: refs/heads/master@{#16197}
diff --git a/webrtc/api/webrtcsession_unittest.cc b/webrtc/api/webrtcsession_unittest.cc
index c8ae058..1a7a026 100644
--- a/webrtc/api/webrtcsession_unittest.cc
+++ b/webrtc/api/webrtcsession_unittest.cc
@@ -50,6 +50,12 @@
 #include "webrtc/pc/channelmanager.h"
 #include "webrtc/pc/mediasession.h"
 
+#define MAYBE_SKIP_TEST(feature)                    \
+  if (!(feature())) {                               \
+    LOG(LS_INFO) << "Feature disabled... skipping"; \
+    return;                                         \
+  }
+
 using cricket::FakeVoiceMediaChannel;
 using cricket::TransportInfo;
 using rtc::SocketAddress;
@@ -1844,6 +1850,7 @@
 // Test that we accept an offer with a DTLS fingerprint when DTLS is on
 // and that we return an answer with a DTLS fingerprint.
 TEST_P(WebRtcSessionTest, TestReceiveDtlsOfferCreateDtlsAnswer) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   SendAudioVideoStream1();
   InitWithDtls(GetParam());
   SetFactoryDtlsSrtp();
@@ -1872,6 +1879,7 @@
 // Test that we set a local offer with a DTLS fingerprint when DTLS is on
 // and then we accept a remote answer with a DTLS fingerprint successfully.
 TEST_P(WebRtcSessionTest, TestCreateDtlsOfferReceiveDtlsAnswer) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   SendAudioVideoStream1();
   InitWithDtls(GetParam());
   SetFactoryDtlsSrtp();
@@ -1901,6 +1909,7 @@
 // Test that if we support DTLS and the other side didn't offer a fingerprint,
 // we will fail to set the remote description.
 TEST_P(WebRtcSessionTest, TestReceiveNonDtlsOfferWhenDtlsOn) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   cricket::MediaSessionOptions options;
   options.recv_video = true;
@@ -1924,6 +1933,7 @@
 // Test that we return a failure when applying a local answer that doesn't have
 // a DTLS fingerprint when DTLS is required.
 TEST_P(WebRtcSessionTest, TestSetLocalNonDtlsAnswerWhenDtlsOn) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   SessionDescriptionInterface* offer = NULL;
   SessionDescriptionInterface* answer = NULL;
@@ -1939,6 +1949,7 @@
 // Test that we return a failure when applying a remote answer that doesn't have
 // a DTLS fingerprint when DTLS is required.
 TEST_P(WebRtcSessionTest, TestSetRemoteNonDtlsAnswerWhenDtlsOn) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   SessionDescriptionInterface* offer = CreateOffer();
   cricket::MediaSessionOptions options;
@@ -3915,6 +3926,8 @@
 }
 
 TEST_P(WebRtcSessionTest, TestRtpDataChannelConstraintTakesPrecedence) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
+
   configuration_.enable_rtp_data_channel = true;
   options_.disable_sctp_data_channels = false;
 
@@ -3927,6 +3940,7 @@
 // Test that sctp_content_name/sctp_transport_name (used for stats) are correct
 // before and after BUNDLE is negotiated.
 TEST_P(WebRtcSessionTest, SctpContentAndTransportName) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   SetFactoryDtlsSrtp();
   InitWithDtls(GetParam());
 
@@ -3960,6 +3974,8 @@
 }
 
 TEST_P(WebRtcSessionTest, TestCreateOfferWithSctpEnabledWithoutStreams) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
+
   InitWithDtls(GetParam());
 
   std::unique_ptr<SessionDescriptionInterface> offer(CreateOffer());
@@ -3968,6 +3984,7 @@
 }
 
 TEST_P(WebRtcSessionTest, TestCreateAnswerWithSctpInOfferAndNoStreams) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   SetFactoryDtlsSrtp();
   InitWithDtls(GetParam());
 
@@ -3999,6 +4016,8 @@
 // Test that if DTLS is enabled, we end up with an SctpTransport created
 // (and not an RtpDataChannel).
 TEST_P(WebRtcSessionTest, TestSctpDataChannelWithDtls) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
+
   InitWithDtls(GetParam());
 
   SetLocalDescriptionWithDataChannel();
@@ -4009,6 +4028,7 @@
 // Test that if SCTP is disabled, we don't end up with an SctpTransport
 // created (or an RtpDataChannel).
 TEST_P(WebRtcSessionTest, TestDisableSctpDataChannels) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   options_.disable_sctp_data_channels = true;
   InitWithDtls(GetParam());
 
@@ -4018,6 +4038,7 @@
 }
 
 TEST_P(WebRtcSessionTest, TestSctpDataChannelSendPortParsing) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   const int new_send_port = 9998;
   const int new_recv_port = 7775;
 
@@ -4059,6 +4080,8 @@
 // WebRtcSession signals the SctpTransport creation request with the expected
 // config.
 TEST_P(WebRtcSessionTest, TestSctpDataChannelOpenMessage) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
+
   InitWithDtls(GetParam());
 
   SetLocalDescriptionWithDataChannel();
@@ -4098,6 +4121,7 @@
 // identity generation is finished (even if a certificate is provided this is
 // an async op).
 TEST_P(WebRtcSessionTest, TestCreateOfferBeforeIdentityRequestReturnSuccess) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
 
   EXPECT_TRUE(session_->waiting_for_certificate_for_testing());
@@ -4113,6 +4137,7 @@
 // identity generation is finished (even if a certificate is provided this is
 // an async op).
 TEST_P(WebRtcSessionTest, TestCreateAnswerBeforeIdentityRequestReturnSuccess) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   SetFactoryDtlsSrtp();
 
@@ -4133,6 +4158,7 @@
 // identity generation is finished (even if a certificate is provided this is
 // an async op).
 TEST_P(WebRtcSessionTest, TestCreateOfferAfterIdentityRequestReturnSuccess) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
 
   EXPECT_TRUE_WAIT(!session_->waiting_for_certificate_for_testing(), 1000);
@@ -4144,6 +4170,7 @@
 // Verifies that CreateOffer fails when CreateOffer is called after async
 // identity generation fails.
 TEST_F(WebRtcSessionTest, TestCreateOfferAfterIdentityRequestReturnFailure) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtlsIdentityGenFail();
 
   EXPECT_TRUE_WAIT(!session_->waiting_for_certificate_for_testing(), 1000);
@@ -4156,6 +4183,7 @@
 // before async identity generation is finished.
 TEST_P(WebRtcSessionTest,
        TestMultipleCreateOfferBeforeIdentityRequestReturnSuccess) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   VerifyMultipleAsyncCreateDescription(GetParam(),
                                        CreateSessionDescriptionRequest::kOffer);
 }
@@ -4164,6 +4192,7 @@
 // before async identity generation fails.
 TEST_F(WebRtcSessionTest,
        TestMultipleCreateOfferBeforeIdentityRequestReturnFailure) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   VerifyMultipleAsyncCreateDescriptionIdentityGenFailure(
       CreateSessionDescriptionRequest::kOffer);
 }
@@ -4172,6 +4201,7 @@
 // before async identity generation is finished.
 TEST_P(WebRtcSessionTest,
        TestMultipleCreateAnswerBeforeIdentityRequestReturnSuccess) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   VerifyMultipleAsyncCreateDescription(
       GetParam(), CreateSessionDescriptionRequest::kAnswer);
 }
@@ -4180,6 +4210,7 @@
 // before async identity generation fails.
 TEST_F(WebRtcSessionTest,
        TestMultipleCreateAnswerBeforeIdentityRequestReturnFailure) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   VerifyMultipleAsyncCreateDescriptionIdentityGenFailure(
       CreateSessionDescriptionRequest::kAnswer);
 }
@@ -4223,6 +4254,7 @@
 // Tests that we can renegotiate new media content with ICE candidates in the
 // new remote SDP.
 TEST_P(WebRtcSessionTest, TestRenegotiateNewMediaWithCandidatesInSdp) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   SetFactoryDtlsSrtp();
 
@@ -4252,6 +4284,7 @@
 // Tests that we can renegotiate new media content with ICE candidates separated
 // from the remote SDP.
 TEST_P(WebRtcSessionTest, TestRenegotiateNewMediaWithCandidatesSeparated) {
+  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   InitWithDtls(GetParam());
   SetFactoryDtlsSrtp();