fundingmgr+channelnotifier: add channel config to pending chan ntfn

To be able to write a new channel backup file for pending channels,
we need to include the channel configuration in the pending channel
notification event.

channelnotifier/channelnotifier.go

@@ -23,8 +23,14 @@ type ChannelNotifier struct {
 // PendingOpenChannelEvent represents a new event where a new channel has
 // entered a pending open state.
 type PendingOpenChannelEvent struct {
-	// ChannelPoint is the channelpoint for the new channel.
+	// ChannelPoint is the channel outpoint for the new channel.
 	ChannelPoint *wire.OutPoint
+
+	// PendingChannel is the channel configuration for the newly created
+	// channel. This might not have been persisted to the channel DB yet
+	// because we are still waiting for the final message from the remote
+	// peer.
+	PendingChannel *channeldb.OpenChannel
 }
 
 // OpenChannelEvent represents a new event where a channel goes from pending
@@ -89,10 +95,18 @@ func (c *ChannelNotifier) SubscribeChannelEvents() (*subscribe.Client, error) {
 	return c.ntfnServer.Subscribe()
 }
 
-// NotifyPendingOpenChannelEvent notifies the channelEventNotifier goroutine that a
-// new channel is pending.
-func (c *ChannelNotifier) NotifyPendingOpenChannelEvent(chanPoint wire.OutPoint) {
-	event := PendingOpenChannelEvent{ChannelPoint: &chanPoint}
+// NotifyPendingOpenChannelEvent notifies the channelEventNotifier goroutine
+// that a new channel is pending. The pending channel is passed as a parameter
+// instead of read from the database because it might not yet have been
+// persisted to the DB because we still wait for the final message from the
+// remote peer.
+func (c *ChannelNotifier) NotifyPendingOpenChannelEvent(chanPoint wire.OutPoint,
+	pendingChan *channeldb.OpenChannel) {
+
+	event := PendingOpenChannelEvent{
+		ChannelPoint:   &chanPoint,
+		PendingChannel: pendingChan,
+	}
 
 	if err := c.ntfnServer.SendUpdate(event); err != nil {
 		log.Warnf("Unable to send pending open channel update: %v", err)