Use continual gathering to restore backup connections

webrtc/p2p/client/basicportallocator.cc

Index: webrtc/p2p/client/basicportallocator.cc
diff --git a/webrtc/p2p/client/basicportallocator.cc b/webrtc/p2p/client/basicportallocator.cc
index 20fc84a38a22fc05eeed1942a1231a1ba94aaf27..4bba1e615c038076bdf3411b71937082ee110a4e 100644
--- a/webrtc/p2p/client/basicportallocator.cc
+++ b/webrtc/p2p/client/basicportallocator.cc
@@ -215,6 +215,18 @@ void BasicPortAllocatorSession::ClearGettingPorts() {
     sequences_[i]->Stop();
 }
 
+void BasicPortAllocatorSession::InactivateNetworksInExistingSequences(

[Taylor Brandstetter, 2016/06/06 18:18:37]

On second thought... If this method is always intended to be used along with
"StartGettingPorts" in order to re-gather ports for specific networks, it would
be better to just call the method "RegatherPortsForNetworks()". That creates a
looser dependency on the implementation of the PortAllocator; developers may
implement their own PortAllocator, where it's not clear what they're supposed to
do when "InactivateNetworks" is called.

Also, document in the header file what a nullptr parameter means.

[honghaiz3, 2016/06/07 16:42:06]

Done, except the name. 
We are not re-gathering "port". What it does is to create ports and re-gathering
candidates. I use the name GetPortsOnNetworks (similar to StartGettingPorts). 

+    std::vector<rtc::Network*>* networks) {
+  for (AllocationSequence* sequence : sequences_) {
+    if (!sequence->network_inactive() &&
+        (!networks ||
+         std::find(networks->begin(), networks->end(), sequence->network()) !=
+             networks->end())) {
+      sequence->OnNetworkInactivated();
+    }
+  }
+}
+
 std::vector<PortInterface*> BasicPortAllocatorSession::ReadyPorts() const {
   std::vector<PortInterface*> ret;
   for (const PortData& port : ports_) {
@@ -501,10 +513,10 @@ void BasicPortAllocatorSession::OnNetworksChanged() {
   for (AllocationSequence* sequence : sequences_) {
     // Remove the network from the allocation sequence if it is not in
     // |networks|.
-    if (!sequence->network_removed() &&
+    if (!sequence->network_inactive() &&
         std::find(networks.begin(), networks.end(), sequence->network()) ==
             networks.end()) {
-      sequence->OnNetworkRemoved();
+      sequence->OnNetworkInactivated();
     }
   }
 
@@ -793,10 +805,10 @@ void AllocationSequence::Clear() {
   turn_ports_.clear();
 }
 
-void AllocationSequence::OnNetworkRemoved() {
+void AllocationSequence::OnNetworkInactivated() {
   // Stop the allocation sequence if its network is gone.
+  network_inactive_ = true;
   Stop();
-  network_removed_ = true;
 }
 
 AllocationSequence::~AllocationSequence() {
@@ -805,8 +817,8 @@ AllocationSequence::~AllocationSequence() {
 
 void AllocationSequence::DisableEquivalentPhases(rtc::Network* network,
     PortConfiguration* config, uint32_t* flags) {
-  if (network_removed_) {
-    // If the network of this allocation sequence has ever gone away,
+  if (network_inactive_) {
+    // If the network of this allocation sequence has ever become inactive,
     // it won't be equivalent to the new network.
     return;
   }