Add interface for scoped keeper for transfer module (#2034)

## Description

Add scoped keeper interface for transfer module keeper.

Part of: #2020

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [ ] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

CHANGELOG.md

@@ -59,6 +59,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (modules/core/exported) [\#1107](https://github.com/cosmos/ibc-go/pull/1107) Merging the `Header` and `Misbehaviour` interfaces into a single `ClientMessage` type.
 * (06-solomachine)[\#1906](https://github.com/cosmos/ibc-go/pull/1906/files) Removed `AllowUpdateAfterProposal` boolean as it has been deprecated (see 01_concepts of the solo machine spec for more details).
 * (07-tendermint) [\#1896](https://github.com/cosmos/ibc-go/pull/1896) Remove error return from `IterateConsensusStateAscending` in `07-tendermint`.
+* (transfer) [\#2034](https://github.com/cosmos/ibc-go/pull/2034) Transfer Keeper now expects a keeper which fulfills the expected `ScopedKeeper` interface for the capability keeper.
 * (05-port) [\#2025](https://github.com/cosmos/ibc-go/pull/2025) Port Keeper now expects a keeper which fulfills the expected `ScopedKeeper` interface for the capability keeper.
 * (04-channel) [\#2024](https://github.com/cosmos/ibc-go/pull/2024) Channel Keeper now expects a keeper which fulfills the expected `ScopedKeeper` interface for the capability keeper.
 

modules/apps/transfer/keeper/keeper.go

@@ -5,7 +5,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/store/prefix"
 	storetypes "github.com/cosmos/cosmos-sdk/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	capabilitykeeper "github.com/cosmos/cosmos-sdk/x/capability/keeper"
 	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
 	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
@@ -26,14 +25,14 @@ type Keeper struct {
 	portKeeper    types.PortKeeper
 	authKeeper    types.AccountKeeper
 	bankKeeper    types.BankKeeper
-	scopedKeeper  capabilitykeeper.ScopedKeeper
+	scopedKeeper  types.ScopedKeeper
 }
 
 // NewKeeper creates a new IBC transfer Keeper instance
 func NewKeeper(
 	cdc codec.BinaryCodec, key storetypes.StoreKey, paramSpace paramtypes.Subspace,
 	ics4Wrapper types.ICS4Wrapper, channelKeeper types.ChannelKeeper, portKeeper types.PortKeeper,
-	authKeeper types.AccountKeeper, bankKeeper types.BankKeeper, scopedKeeper capabilitykeeper.ScopedKeeper,
+	authKeeper types.AccountKeeper, bankKeeper types.BankKeeper, scopedKeeper types.ScopedKeeper,
 ) Keeper {
 	// ensure ibc transfer module account is set
 	if addr := authKeeper.GetModuleAddress(types.ModuleName); addr == nil {

modules/apps/transfer/types/expected_keepers.go

@@ -51,3 +51,11 @@ type ConnectionKeeper interface {
 type PortKeeper interface {
 	BindPort(ctx sdk.Context, portID string) *capabilitytypes.Capability
 }
+
+// ScopedKeeper defines the expected x/capability scoped keeper interface
+type ScopedKeeper interface {
+	GetCapability(ctx sdk.Context, name string) (*capabilitytypes.Capability, bool)
+	AuthenticateCapability(ctx sdk.Context, cap *capabilitytypes.Capability, name string) bool
+	LookupModules(ctx sdk.Context, name string) ([]string, *capabilitytypes.Capability, error)
+	ClaimCapability(ctx sdk.Context, cap *capabilitytypes.Capability, name string) error
+}