Remove toIncludedMetrics() one-liner

Inlining container.AllMetrics.Difference() call makes the code intent
more explicit, and is about same amount of code.

Author: eero-t

cmd/cadvisor.go

@@ -121,7 +121,7 @@ func main() {
 	if len(enableMetrics) > 0 {
 		includedMetrics = enableMetrics
 	} else {
-		includedMetrics = toIncludedMetrics(ignoreMetrics)
+		includedMetrics = container.AllMetrics.Difference(ignoreMetrics)
 	}
 	klog.V(1).Infof("enabled metrics: %s", includedMetrics.String())
 	setMaxProcs()
@@ -239,7 +239,3 @@ func createCollectorHttpClient(collectorCert, collectorKey string) http.Client {
 
 	return http.Client{Transport: transport}
 }
-
-func toIncludedMetrics(ignoreMetrics container.MetricSet) container.MetricSet {
-	return container.AllMetrics.Difference(ignoreMetrics)
-}

cmd/cadvisor_test.go

@@ -118,7 +118,7 @@ func TestToIncludedMetrics(t *testing.T) {
 	}
 
 	for idx, ignore := range ignores {
-		actual := toIncludedMetrics(ignore)
+		actual := container.AllMetrics.Difference(ignore)
 		assert.Equal(t, actual, expected[idx])
 	}
 }