Add config to prune TURN ports

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..bddb3967e544b37ff3ea62039903a9d6091de3e1 100644
--- a/webrtc/p2p/client/basicportallocator.h
+++ b/webrtc/p2p/client/basicportallocator.h
@@ -123,7 +123,15 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
     bool has_pairable_candidate() const { return has_pairable_candidate_; }
     bool complete() const { return state_ == STATE_COMPLETE; }
     bool error() const { return state_ == STATE_ERROR; }
+    bool pruned() const { return state_ == STATE_PRUNED; }
+    bool inprogress() const { return state_ == STATE_INPROGRESS; }
+    // Returns true if this port is ready to be used.
+    bool ready() const {
+      return has_pairable_candidate_ && state_ != STATE_ERROR &&
+             state_ != STATE_PRUNED;
+    }
 
+    void set_pruned() { state_ = STATE_PRUNED; }
     void set_has_pairable_candidate(bool has_pairable_candidate) {
       if (has_pairable_candidate) {
         ASSERT(state_ == STATE_INPROGRESS);
@@ -142,7 +150,9 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
     enum State {
       STATE_INPROGRESS,  // Still gathering candidates.
       STATE_COMPLETE,    // All candidates allocated and ready for process.
-      STATE_ERROR        // Error in gathering candidates.
+      STATE_ERROR,       // Error in gathering candidates.
+      STATE_PRUNED       // Pruned by higher priority ports on the same network
+                         // interface. Only TURN ports may be pruned.
     };
     Port* port_ = nullptr;
     AllocationSequence* sequence_ = nullptr;
@@ -178,6 +188,10 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
   // in order to avoid leaking any information.
   Candidate SanitizeRelatedAddress(const Candidate& c) const;
 
+  Port* GetBestTurnPortForNetwork(const std::string& network_name) const;
+  // Returns true if at least one TURN port is pruned.
+  bool PruneTurnPorts(Port* newly_pairable_turn_port);
+
   BasicPortAllocator* allocator_;
   rtc::Thread* network_thread_;
   std::unique_ptr<rtc::PacketSocketFactory> owned_socket_factory_;
@@ -190,6 +204,8 @@ class BasicPortAllocatorSession : public PortAllocatorSession,
   std::vector<AllocationSequence*> sequences_;
   std::vector<PortData> ports_;
   uint32_t candidate_filter_ = CF_ALL;
+  // Whether to prune low-priority ports, taken from the port allocator.
+  bool prune_turn_ports_;
 
   friend class AllocationSequence;
 };