Use continual gathering to restore backup connections

webrtc/p2p/base/port.cc

Index: webrtc/p2p/base/port.cc
diff --git a/webrtc/p2p/base/port.cc b/webrtc/p2p/base/port.cc
index 909843c62faae319cbec8975c201abf233d4f16d..0b7583aa0e532f0b2ec234cdd4a4882983f3cc97 100644
--- a/webrtc/p2p/base/port.cc
+++ b/webrtc/p2p/base/port.cc
@@ -237,6 +237,12 @@ Connection* Port::GetConnection(const rtc::SocketAddress& remote_addr) {
     return NULL;
 }
 
+void Port::FailAndDestroyConnections() {
+  for (auto kv : connections_) {
+    kv.second->FailAndDestroy();
+  }
+}
+
 void Port::AddAddress(const rtc::SocketAddress& address,
                       const rtc::SocketAddress& base_address,
                       const rtc::SocketAddress& related_address,