routing/payment_session: make RequestRoute take max amt, fee limit and

active shards

In preparation for doing pathfinding for routes sending a value less
than the total payment amount, we let the payment session take the max
amount to send and the fee limit as arguments to RequestRoute.

routing/payment_lifecycle.go

@@ -31,6 +31,8 @@ func (e errNoRoute) Error() string {
 // needed to resume if from any point.
 type paymentLifecycle struct {
 	router        *ChannelRouter
+	totalAmount   lnwire.MilliSatoshi
+	feeLimit      lnwire.MilliSatoshi
 	paymentHash   lntypes.Hash
 	paySession    PaymentSession
 	timeoutChan   <-chan time.Time
@@ -267,7 +269,9 @@ func (p *paymentLifecycle) createNewPaymentAttempt() (lnwire.ShortChannelID,
 	}
 
 	// Create a new payment attempt from the given payment session.
-	rt, err := p.paySession.RequestRoute(uint32(p.currentHeight))
+	rt, err := p.paySession.RequestRoute(
+		p.totalAmount, p.feeLimit, 0, uint32(p.currentHeight),
+	)
 	if err != nil {
 		log.Warnf("Failed to find route for payment %x: %v",
 			p.paymentHash, err)