lnwallet: integrate obfuscated state hints into funding workflow

This commit finalizes the implementation of #58 by integrating passing
around the obfuscate state hints into the funding workflow of the
wallet, and also the daemon’s funding manager.

In order to amend the tests, the functions to set and receive the state
hints are now publicly exported.

lnwallet/reservation.go

@@ -324,8 +324,10 @@ func (r *ChannelReservation) CompleteReservation(fundingInputScripts []*InputScr
 // the .OurSignatures() method. As this method should only be called as a
 // response to a single funder channel, only a commitment signature will be
 // populated.
-func (r *ChannelReservation) CompleteReservationSingle(revocationKey *btcec.PublicKey,
-	fundingPoint *wire.OutPoint, commitSig []byte) error {
+func (r *ChannelReservation) CompleteReservationSingle(
+	revocationKey *btcec.PublicKey, fundingPoint *wire.OutPoint,
+	commitSig []byte, obsfucator [StateHintSize]byte) error {
+
 	errChan := make(chan error, 1)
 
 	r.wallet.msgChan <- &addSingleFunderSigsMsg{
@@ -333,6 +335,7 @@ func (r *ChannelReservation) CompleteReservationSingle(revocationKey *btcec.Publ
 		revokeKey:          revocationKey,
 		fundingOutpoint:    fundingPoint,
 		theirCommitmentSig: commitSig,
+		obsfucator:         obsfucator,
 		err:                errChan,
 	}
 
@@ -395,6 +398,19 @@ func (r *ChannelReservation) FundingOutpoint() *wire.OutPoint {
 	return r.partialState.FundingOutpoint
 }
 
+// StateNumObfuscator returns the bytes to be used to obsfucate the state
+// number hints for all future states of the commitment transaction for this
+// workflow.
+//
+// NOTE: This value will only be available for a single funder workflow after
+// the CompleteReservation or CompleteReservationSingle methods have been
+// successfully executed.
+func (r *ChannelReservation) StateNumObfuscator() [StateHintSize]byte {
+	r.RLock()
+	defer r.RUnlock()
+	return r.partialState.StateHintObsfucator
+}
+
 // Cancel abandons this channel reservation. This method should be called in
 // the scenario that communications with the counterparty break down. Upon
 // cancellation, all resources previously reserved for this pending payment