core, eth/downloader: expose the bad hashes, check in downloader

core/manager.go

@@ -3,9 +3,7 @@ package core
 import (
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/eth/downloader"
 	"github.com/ethereum/go-ethereum/event"
-	"github.com/ethereum/go-ethereum/p2p"
 )
 
 // TODO move this to types?
@@ -14,11 +12,7 @@ type Backend interface {
 	BlockProcessor() *BlockProcessor
 	ChainManager() *ChainManager
 	TxPool() *TxPool
-	PeerCount() int
-	IsListening() bool
-	Peers() []*p2p.Peer
 	BlockDb() common.Database
 	StateDb() common.Database
 	EventMux() *event.TypeMux
-	Downloader() *downloader.Downloader
 }