Reland the CL to remove candidates when doing continual gathering

webrtc/api/jsepicecandidate.cc

 /*
  *  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 61 matching lines @@
     if ((*it)->sdp_mid() == candidate->sdp_mid() &&
         (*it)->sdp_mline_index() == candidate->sdp_mline_index() &&
         (*it)->candidate().IsEquivalent(candidate->candidate())) {
       ret = true;
       break;
     }
   }
   return ret;
 }
 
+size_t JsepCandidateCollection::remove(const cricket::Candidate& candidate) {
+  auto iter = std::find_if(candidates_.begin(), candidates_.end(),
+                           [candidate](JsepIceCandidate* c) {
+                             return candidate.MatchesForRemoval(c->candidate());
+                           });
+  if (iter != candidates_.end()) {
+    delete *iter;
+    candidates_.erase(iter);
+    return 1;
+  }
+  return 0;
+}
+
 }  // namespace webrtc