Check if a room looks like a DM rooms on joining

and mark it as one if so.

Also change the heuristic to only count rooms with 2 total members rather than 2 joined members, otherwise this is going to mark any room as a DM if someone creates a room, invites a bunch of people and you happen to be first to join.

src/Rooms.js

@@ -68,7 +68,7 @@ export function looksLikeDirectMessageRoom(room, me) {
         // Used to split rooms via tags
         const tagNames = Object.keys(room.tags);
         // Used for 1:1 direct chats
-        const joinedMembers = room.getJoinedMembers();
+        const joinedMembers = room.currentState.getMembers();
 
         // Show 1:1 chats in seperate "Direct Messages" section as long as they haven't
         // been moved to a different tag section

src/components/structures/RoomView.js

@@ -451,6 +451,7 @@ module.exports = React.createClass({
                 room: room,
                 joining: false,
             });
+
             this._onRoomLoaded(room);
         }
     },
@@ -520,6 +521,17 @@ module.exports = React.createClass({
         // into.
         var me = MatrixClientPeg.get().credentials.userId;
         if (this.state.joining && this.state.room.hasMembershipState(me, "join")) {
+            // Having just joined a room, check to see if it looks like a DM room, and if so,
+            // mark it as one. This is to work around the fact that some clients don't support
+            // is_direct. We should remove this once they do.
+            const me = this.state.room.getMember(MatrixClientPeg.get().credentials.userId);
+            if (Rooms.looksLikeDirectMessageRoom(this.state.room, me)) {
+                // XXX: There's not a whole lot we can really do if this fails: at best
+                // perhaps we could try a couple more times, but since it's a temporary
+                // compatability workaround, let's not bother.
+                Rooms.setDMRoom(this.state.room.roomId, me.events.member.getSender()).done();
+            }
+
             this.setState({
                 joining: false
             });