Refactor util clock into it's own pkg

pkg/client/cache/expiration_cache.go

@@ -21,7 +21,7 @@ import (
 	"time"
 
 	"github.com/golang/glog"
-	"k8s.io/kubernetes/pkg/util"
+	"k8s.io/kubernetes/pkg/util/clock"
 )
 
 // ExpirationCache implements the store interface
@@ -38,7 +38,7 @@ import (
 type ExpirationCache struct {
 	cacheStorage     ThreadSafeStore
 	keyFunc          KeyFunc
-	clock            util.Clock
+	clock            clock.Clock
 	expirationPolicy ExpirationPolicy
 	// expirationLock is a write lock used to guarantee that we don't clobber
 	// newly inserted objects because of a stale expiration timestamp comparison
@@ -58,7 +58,7 @@ type TTLPolicy struct {
 	Ttl time.Duration
 
 	// Clock used to calculate ttl expiration
-	Clock util.Clock
+	Clock clock.Clock
 }
 
 // IsExpired returns true if the given object is older than the ttl, or it can't
@@ -202,7 +202,7 @@ func NewTTLStore(keyFunc KeyFunc, ttl time.Duration) Store {
 	return &ExpirationCache{
 		cacheStorage:     NewThreadSafeStore(Indexers{}, Indices{}),
 		keyFunc:          keyFunc,
-		clock:            util.RealClock{},
-		expirationPolicy: &TTLPolicy{ttl, util.RealClock{}},
+		clock:            clock.RealClock{},
+		expirationPolicy: &TTLPolicy{ttl, clock.RealClock{}},
 	}
 }