VENOM-443: Prepare for persistent groupchats

* Prepare for TokTok/c-toxcore#1156 to be merged
* Restore known groupchats from chatlist

Author: naxuroqa

src/testing/mocks/MockToxSession.vala

@@ -198,6 +198,9 @@ namespace Mock {
                      .create();
       return mock().actual_call(this, "conference_get_title", args).get_string();
     }
+    public Gee.Iterable<uint32> conference_get_chatlist() {
+      return (Gee.Iterable<uint32>) mock().actual_call(this, "conference_get_chatlist").get_object();
+    }
     public void file_control(uint32 friend_number, uint32 file_number, ToxCore.FileControl control) throws ToxError {
       var args = Arguments.builder()
                      .uint(friend_number)

src/tox/ToxAdapterConferenceListener.vala

@@ -50,6 +50,10 @@ namespace Venom {
       this.session = session;
       session.set_conference_listener(this);
       friends = session.get_friends();
+      var chatlist = session.conference_get_chatlist();
+      foreach (var conference_number in chatlist) {
+        on_conference_new(conference_number, "");
+      }
     }
 
     public virtual void on_remove_conference(IContact c) throws Error {

src/tox/ToxSession.vala

@@ -84,6 +84,7 @@ namespace Venom {
     public abstract void conference_delete(uint32 conference_number) throws ToxError;
     public abstract void conference_invite(uint32 friend_number, uint32 conference_number) throws ToxError;
     public abstract void conference_join(uint32 friend_number, ConferenceType type, uint8[] cookie) throws ToxError;
+    public abstract Gee.Iterable<uint32> conference_get_chatlist();
 
     public abstract void conference_send_message(uint32 conference_number, string message) throws ToxError;
     public abstract void conference_set_title(uint32 conference_number, string title) throws ToxError;
@@ -838,6 +839,15 @@ namespace Venom {
       }
     }
 
+    public Gee.Iterable<uint32> conference_get_chatlist() {
+      var chatlist = handle.conference_get_chatlist();
+      var list = new Gee.ArrayList<uint32>();
+      foreach (var c in chatlist) {
+        list.add(c);
+      }
+      return list;
+    }
+
     public void @lock() {
       mutex.@lock();
     }