Accept SDP with TRANSPORT attributes missing from bundled m= sections.

webrtc/p2p/base/transportdescriptionfactory.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 35 matching lines @@
   // Specifies the certificate to use (only used when secure != SEC_DISABLED).
   void set_certificate(
       const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
     certificate_ = certificate;
   }
 
   // Creates a transport description suitable for use in an offer.
   TransportDescription* CreateOffer(const TransportOptions& options,
       const TransportDescription* current_description) const;
   // Create a transport description that is a response to an offer.
+  //
+  // If |require_transport_attributes| is true, then TRANSPORT category
+  // attributes are expected to be present in |offer|, as defined by
+  // sdp-mux-attributes, and null will be returned otherwise. It's expected
+  // that this will be set to false for an m= section that's in a BUNDLE group
+  // but isn't the first m= section in the group.
   TransportDescription* CreateAnswer(
       const TransportDescription* offer,
       const TransportOptions& options,
+      bool require_transport_attributes,
       const TransportDescription* current_description) const;
 
  private:
   bool SetSecurityInfo(TransportDescription* description,
                        ConnectionRole role) const;
 
   SecurePolicy secure_;
   rtc::scoped_refptr<rtc::RTCCertificate> certificate_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_TRANSPORTDESCRIPTIONFACTORY_H_