Add interface for scoped keeper for 04-channel (#2024)

## Description

Add scoped keeper interface for 04-channel module.

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`.
+* (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.
 
 ### State Machine Breaking
 

modules/core/04-channel/keeper/keeper.go

@@ -8,7 +8,6 @@ import (
 	storetypes "github.com/cosmos/cosmos-sdk/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	capabilitykeeper "github.com/cosmos/cosmos-sdk/x/capability/keeper"
 	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
 	"github.com/tendermint/tendermint/libs/log"
 	db "github.com/tendermint/tm-db"
@@ -33,14 +32,14 @@ type Keeper struct {
 	clientKeeper     types.ClientKeeper
 	connectionKeeper types.ConnectionKeeper
 	portKeeper       types.PortKeeper
-	scopedKeeper     capabilitykeeper.ScopedKeeper
+	scopedKeeper     types.ScopedKeeper
 }
 
 // NewKeeper creates a new IBC channel Keeper instance
 func NewKeeper(
 	cdc codec.BinaryCodec, key storetypes.StoreKey,
 	clientKeeper types.ClientKeeper, connectionKeeper types.ConnectionKeeper,
-	portKeeper types.PortKeeper, scopedKeeper capabilitykeeper.ScopedKeeper,
+	portKeeper types.PortKeeper, scopedKeeper types.ScopedKeeper,
 ) Keeper {
 	return Keeper{
 		storeKey:         key,

modules/core/04-channel/types/expected_keepers.go

@@ -76,3 +76,10 @@ type ConnectionKeeper interface {
 type PortKeeper interface {
 	Authenticate(ctx sdk.Context, key *capabilitytypes.Capability, portID string) bool
 }
+
+// ScopedKeeper defines the expected x/capability scoped keeper interface
+type ScopedKeeper interface {
+	NewCapability(ctx sdk.Context, name string) (*capabilitytypes.Capability, error)
+	AuthenticateCapability(ctx sdk.Context, cap *capabilitytypes.Capability, name string) bool
+	LookupModules(ctx sdk.Context, name string) ([]string, *capabilitytypes.Capability, error)
+}