Revert of Replacing DtlsIdentityStoreInterface with RTCCertificateGeneratorInterface.

webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm

Index: webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm b/webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm
index 6ccf54edafa976931a8d07a1e1a6988684e0cef1..3fcc652e69b3d69b66c21d366e6223f4e787f6f7 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm
+++ b/webrtc/sdk/objc/Framework/Classes/RTCPeerConnection.mm
@@ -226,12 +226,11 @@
     std::unique_ptr<webrtc::MediaConstraints> nativeConstraints =
         constraints.nativeConstraints;
     _peerConnection =
-        factory.nativeFactory->CreatePeerConnection(
-            *config,
-            nativeConstraints.get(),
-            nullptr,
-            std::unique_ptr<rtc::RTCCertificateGeneratorInterface>(),
-            _observer.get());
+        factory.nativeFactory->CreatePeerConnection(*config,
+                                                    nativeConstraints.get(),
+                                                    nullptr,
+                                                    nullptr,
+                                                    _observer.get());
     _localStreams = [[NSMutableArray alloc] init];
     _delegate = delegate;
   }