Added DtlsCertificate, a ref counted object owning an SSLIdentity

webrtc/p2p/base/transportdescriptionfactory.cc

Index: webrtc/p2p/base/transportdescriptionfactory.cc
diff --git a/webrtc/p2p/base/transportdescriptionfactory.cc b/webrtc/p2p/base/transportdescriptionfactory.cc
index 1230ba52c18dee87447875245c289e048a47f21a..2c3f5fdf248cdc7ec82ebf3d73667f1cb44f86d8 100644
--- a/webrtc/p2p/base/transportdescriptionfactory.cc
+++ b/webrtc/p2p/base/transportdescriptionfactory.cc
@@ -24,7 +24,7 @@ static TransportProtocol kDefaultProtocol = ICEPROTO_RFC5245;
 TransportDescriptionFactory::TransportDescriptionFactory()
     : protocol_(kDefaultProtocol),
       secure_(SEC_DISABLED),
-      identity_(NULL) {
+      certificate_(nullptr) {
 }
 
 TransportDescription* TransportDescriptionFactory::CreateOffer(
@@ -129,7 +129,7 @@ TransportDescription* TransportDescriptionFactory::CreateAnswer(
 
 bool TransportDescriptionFactory::SetSecurityInfo(
     TransportDescription* desc, ConnectionRole role) const {
-  if (!identity_) {
+  if (!certificate_) {
     LOG(LS_ERROR) << "Cannot create identity digest with no identity";
     return false;
   }
@@ -138,13 +138,14 @@ bool TransportDescriptionFactory::SetSecurityInfo(
   // RFC 4572 Section 5 requires that those lines use the same hash function as
   // the certificate's signature.
   std::string digest_alg;
-  if (!identity_->certificate().GetSignatureDigestAlgorithm(&digest_alg)) {
+  if (!certificate_->identity()->certificate().GetSignatureDigestAlgorithm(
+      &digest_alg)) {
     LOG(LS_ERROR) << "Failed to retrieve the certificate's digest algorithm";
     return false;
   }
 
   desc->identity_fingerprint.reset(
-      rtc::SSLFingerprint::Create(digest_alg, identity_));
+      rtc::SSLFingerprint::Create(digest_alg, certificate_->identity()));
   if (!desc->identity_fingerprint.get()) {
     LOG(LS_ERROR) << "Failed to create identity fingerprint, alg="
                   << digest_alg;