Use continual gathering to restore backup connections

webrtc/p2p/client/basicportallocator.h

Index: webrtc/p2p/client/basicportallocator.h
diff --git a/webrtc/p2p/client/basicportallocator.h b/webrtc/p2p/client/basicportallocator.h
index 8ea66c431e76d560a6299c2831d77a1a83dfeb06..9cae6da668c5eb42b5c8bf6c3210d3e036cb368e 100644
--- a/webrtc/p2p/client/basicportallocator.h
+++ b/webrtc/p2p/client/basicportallocator.h
@@ -47,7 +47,9 @@ class BasicPortAllocator : public PortAllocator {
 
   int network_ignore_mask() const { return network_ignore_mask_; }
 
-  rtc::NetworkManager* network_manager() { return network_manager_; }
+  rtc::NetworkManager* network_manager() const override {
+    return network_manager_;
+  }
 
   // If socket_factory() is set to NULL each PortAllocatorSession
   // creates its own socket factory.
@@ -84,19 +86,36 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
                             const std::string& ice_pwd);
   ~BasicPortAllocatorSession();
 
+  // TODO(honghaiz): When continual gathering is fully enabled, we don't need
+  // the state STATE_STOPPED. A session can always start new allocation
+  // sequences.
+  enum State {
+    STATE_RUNNING,  // Current allocation sequence is running, can start new
+                    // allocation sequences.
+    STATE_CLEARED,  // Current allocation sequence is complete, can start new
+                    // allocation sequences.
+    STATE_STOPPED   // Current allocation sequence is complete, cannot start
+                    // new allocation sequences.
+  };
+
   virtual BasicPortAllocator* allocator() { return allocator_; }
   rtc::Thread* network_thread() { return network_thread_; }
   rtc::PacketSocketFactory* socket_factory() { return socket_factory_; }
 
   void SetCandidateFilter(uint32_t filter) override;
+
   void StartGettingPorts() override;
   void StopGettingPorts() override;
   void ClearGettingPorts() override;
-  bool IsGettingPorts() override { return running_; }
+  bool IsGettingPorts() override { return state_ == STATE_RUNNING; }
+  bool CanGetPorts() override { return state_ != STATE_STOPPED; }
+
   // These will all be cricket::Ports.
   std::vector<PortInterface*> ReadyPorts() const override;
   std::vector<Candidate> ReadyCandidates() const override;
+  std::vector<Candidate> ReadyCandidates(PortInterface* port) const override;
   bool CandidatesAllocationDone() const override;
+  bool RegatherOnFailedNetworks() override;
 
  protected:
   void UpdateIceParametersInternal() override;
@@ -170,7 +189,8 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
   void MaybeSignalCandidatesAllocationDone();
   void OnPortAllocationComplete(AllocationSequence* seq);
   PortData* FindPort(Port* port);
-  void GetNetworks(std::vector<rtc::Network*>* networks);
+  std::vector<rtc::Network*> GetNetworks() const;
+  std::vector<rtc::Network*> GetFailedNetworks() const;
 
   bool CheckCandidateFilter(const Candidate& c) const;
   bool CandidatePairable(const Candidate& c, const Port* port) const;
@@ -184,7 +204,7 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
   rtc::PacketSocketFactory* socket_factory_;
   bool allocation_started_;
   bool network_manager_started_;
-  bool running_;  // set when StartGetAllPorts is called
+  State state_ = STATE_RUNNING;
   bool allocation_sequences_created_;
   std::vector<PortConfiguration*> configs_;
   std::vector<AllocationSequence*> sequences_;
@@ -255,11 +275,15 @@ class AllocationSequence : public rtc::MessageHandler,
   ~AllocationSequence();
   bool Init();
   void Clear();
-  void OnNetworkRemoved();
+  void OnNetworkInactivated();
 
   State state() const { return state_; }
   const rtc::Network* network() const { return network_; }
-  bool network_removed() const { return network_removed_; }
+
+  bool network_inactive() const { return network_inactive_; }
+  void set_network_inactive(bool network_inactive) {
+    network_inactive_ = network_inactive;
+  }
 
   // Disables the phases for a new sequence that this one already covers for an
   // equivalent network setup.
@@ -309,7 +333,7 @@ class AllocationSequence : public rtc::MessageHandler,
   void OnPortDestroyed(PortInterface* port);
 
   BasicPortAllocatorSession* session_;
-  bool network_removed_ = false;
+  bool network_inactive_ = false;
   rtc::Network* network_;
   rtc::IPAddress ip_;
   PortConfiguration* config_;