types.NewCommit (#3275)

* types.NewCommit

* use types.NewCommit everywhere

* fix log in unsafe_reset

* memoize height and round in constructor

* notes about deprecating toVote

* bring back memoizeHeightRound

consensus/replay_test.go

@@ -537,10 +537,8 @@ func makeBlockchainFromWAL(wal WAL) ([]*types.Block, []*types.Commit, error) {
 			}
 		case *types.Vote:
 			if p.Type == types.PrecommitType {
-				thisBlockCommit = &types.Commit{
-					BlockID:    p.BlockID,
-					Precommits: []*types.CommitSig{p.CommitSig()},
-				}
+				commitSigs := []*types.CommitSig{p.CommitSig()}
+				thisBlockCommit = types.NewCommit(p.BlockID, commitSigs)
 			}
 		}
 	}

consensus/state.go

@@ -954,7 +954,7 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 	if cs.Height == 1 {
 		// We're creating a proposal for the first block.
 		// The commit is empty, but not nil.
-		commit = &types.Commit{}
+		commit = types.NewCommit(types.BlockID{}, nil)
 	} else if cs.LastCommit.HasTwoThirdsMajority() {
 		// Make the commit from LastCommit
 		commit = cs.LastCommit.MakeCommit()

consensus/types/round_state_test.go

@@ -53,11 +53,8 @@ func BenchmarkRoundStateDeepCopy(b *testing.B) {
 		Data: types.Data{
 			Txs: txs,
 		},
-		Evidence: types.EvidenceData{},
-		LastCommit: &types.Commit{
-			BlockID:    blockID,
-			Precommits: precommits,
-		},
+		Evidence:   types.EvidenceData{},
+		LastCommit: types.NewCommit(blockID, precommits),
 	}
 	parts := block.MakePartSet(4096)
 	// Random Proposal