Discard old-generation candidates when ICE restarts

talk/app/webrtc/webrtcsession.cc

Index: talk/app/webrtc/webrtcsession.cc
diff --git a/talk/app/webrtc/webrtcsession.cc b/talk/app/webrtc/webrtcsession.cc
index 111a76cf23774081d00ee26e731e41403fc5ef32..33eea57928e865edf7602342ba774b1aeac26cbc 100644
--- a/talk/app/webrtc/webrtcsession.cc
+++ b/talk/app/webrtc/webrtcsession.cc
@@ -492,11 +492,16 @@ class IceRestartAnswerLatch {
     }
   }
 
+  // This method has two purposes: 1. Return whether |new_desc| requests
+  // an ICE restart (i.e., new ufrag/pwd). 2. If it requests an ICE restart
+  // and it is an OFFER, remember this in |ice_restart_| so that the next
+  // Local Answer will be created with new ufrag and pwd.
   bool CheckForRemoteIceRestart(const SessionDescriptionInterface* old_desc,
                                 const SessionDescriptionInterface* new_desc) {
-    if (!old_desc || new_desc->type() != SessionDescriptionInterface::kOffer) {
+    if (!old_desc) {
       return false;
     }
+    bool ice_restart = false;
     const SessionDescription* new_sd = new_desc->description();
     const SessionDescription* old_sd = old_desc->description();
     const ContentInfos& contents = new_sd->contents();
@@ -520,11 +525,15 @@ class IceRestartAnswerLatch {
                                          new_transport_desc->ice_ufrag,
                                          new_transport_desc->ice_pwd)) {
         LOG(LS_INFO) << "Remote peer request ice restart.";
-        ice_restart_ = true;
-        return true;
+        ice_restart = true;
+        break;

[pthatcher1, 2015/12/11 01:49:00]

I think it would be more clear to put this here:

if (new_desc->type() == SessionDescriptionInterface::kOffer) {
  ice_restart_ = true;
}
return true;


(And then return false at the end).

[honghaiz3, 2015/12/11 18:46:10]

Done.

       }
     }
-    return false;
+    if (ice_restart &&
+        new_desc->type() == SessionDescriptionInterface::kOffer) {
+      ice_restart_ = true;
+    }
+    return ice_restart;
   }
 
  private: