fundingmanager: populate additional edge info after adding to graph

This commit serves as another stop-gap for light clients since they are
unable to obtain the capacity and channel point of graph edges. Since
they're aware of these things for their own channels, they can populate
the information within the graph themselves once each channel has been
successfully added to the graph.

fundingmanager.go

@@ -17,6 +17,7 @@ import (
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/discovery"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
@@ -253,10 +254,13 @@ type fundingConfig struct {
 	// announcement from the backing Lightning Network node.
 	CurrentNodeAnnouncement func() (lnwire.NodeAnnouncement, error)
 
-	// SendAnnouncement is used by the FundingManager to send
-	// announcement messages to the Gossiper to possibly broadcast
-	// to the greater network.
-	SendAnnouncement func(msg lnwire.Message) chan error
+	// SendAnnouncement is used by the FundingManager to send announcement
+	// messages to the Gossiper to possibly broadcast to the greater
+	// network. A set of optional message fields can be provided to populate
+	// any information within the graph that is not included in the gossip
+	// message.
+	SendAnnouncement func(msg lnwire.Message,
+		optionalFields ...discovery.OptionalMsgField) chan error
 
 	// NotifyWhenOnline allows the FundingManager to register with a
 	// subsystem that will notify it when the peer comes online. This is
@@ -2140,7 +2144,10 @@ func (f *fundingManager) addToRouterGraph(completeChan *channeldb.OpenChannel,
 
 	// Send ChannelAnnouncement and ChannelUpdate to the gossiper to add
 	// to the Router's topology.
-	errChan := f.cfg.SendAnnouncement(ann.chanAnn)
+	errChan := f.cfg.SendAnnouncement(
+		ann.chanAnn, discovery.ChannelCapacity(completeChan.Capacity),
+		discovery.ChannelPoint(completeChan.FundingOutpoint),
+	)
 	select {
 	case err := <-errChan:
 		if err != nil {