Use continual gathering to restore backup connections

webrtc/p2p/base/fakeportallocator.h

Index: webrtc/p2p/base/fakeportallocator.h
diff --git a/webrtc/p2p/base/fakeportallocator.h b/webrtc/p2p/base/fakeportallocator.h
index 58e1d5fac67d2e674a37055c3d6b7949b3f0ce97..73df118ec0940e01d22f0d81c34f3b82a7fb7ea8 100644
--- a/webrtc/p2p/base/fakeportallocator.h
+++ b/webrtc/p2p/base/fakeportallocator.h
@@ -21,6 +21,7 @@
 #include "webrtc/p2p/base/udpport.h"
 
 namespace rtc {
+class Network;
 class SocketFactory;
 class Thread;
 }
@@ -217,6 +218,7 @@ class FakePortAllocator : public cricket::PortAllocator {
   }
 
   void SetNetworkIgnoreMask(int network_ignore_mask) override {}
+  void GetNetworks(std::vector<rtc::Network*>* networks) const override {}
 
   cricket::PortAllocatorSession* CreateSessionInternal(
       const std::string& content_name,