Reland the CL to remove candidates when doing continual gathering

webrtc/api/jsepicecandidate.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 52 matching lines @@
     return candidates_.size();
   }
   virtual bool HasCandidate(const IceCandidateInterface* candidate) const;
   // Adds and takes ownership of the JsepIceCandidate.
   virtual void add(JsepIceCandidate* candidate) {
     candidates_.push_back(candidate);
   }
   virtual const IceCandidateInterface* at(size_t index) const {
     return candidates_[index];
   }
+  // Removes the candidate that has a matching address and protocol.
+  // Returns the number of candidates that were removed.
+  size_t remove(const cricket::Candidate& candidate);
 
  private:
   std::vector<JsepIceCandidate*> candidates_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(JsepCandidateCollection);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_JSEPICECANDIDATE_H_