Implement current/pending session description methods.

webrtc/api/peerconnectioninterface.h

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 481 matching lines @@
   // break third party projects. As soon as they have been updated this should
   // be changed to "= 0;".
   virtual void GetStats(RTCStatsCollectorCallback* callback) {}
 
   virtual rtc::scoped_refptr<DataChannelInterface> CreateDataChannel(
       const std::string& label,
       const DataChannelInit* config) = 0;
 
   virtual const SessionDescriptionInterface* local_description() const = 0;
   virtual const SessionDescriptionInterface* remote_description() const = 0;
+  // A "current" description the one currently negotiated from a complete
+  // offer/answer exchange.
+  virtual const SessionDescriptionInterface* current_local_description() const {
+    return nullptr;
+  }
+  virtual const SessionDescriptionInterface* current_remote_description()
+      const {
+    return nullptr;
+  }
+  // A "pending" description is one that's part of an incomplete offer/answer
+  // exchange (thus, either an offer or a pranswer). Once the offer/answer
+  // exchange is finished, the "pending" description will become "current".
+  virtual const SessionDescriptionInterface* pending_local_description() const {
+    return nullptr;
+  }
+  virtual const SessionDescriptionInterface* pending_remote_description()
+      const {
+    return nullptr;
+  }
 
   // Create a new offer.
   // The CreateSessionDescriptionObserver callback will be called when done.
   virtual void CreateOffer(CreateSessionDescriptionObserver* observer,
                            const MediaConstraintsInterface* constraints) {}
 
   // TODO(jiayl): remove the default impl and the old interface when chromium
   // code is updated.
   virtual void CreateOffer(CreateSessionDescriptionObserver* observer,
                            const RTCOfferAnswerOptions& options) {}
@@ skipping 329 matching lines @@
     cricket::WebRtcVideoEncoderFactory* encoder_factory,
     cricket::WebRtcVideoDecoderFactory* decoder_factory) {
   return CreatePeerConnectionFactory(
       worker_and_network_thread, worker_and_network_thread, signaling_thread,
       default_adm, encoder_factory, decoder_factory);
 }
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_PEERCONNECTIONINTERFACE_H_