[ObjC ARC] Converts ios/chrome/browser/net:unit_tests to ARC.Automatically generated ARCMigrate c…

ios/chrome/browser/net/metrics_network_client_unittest.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ios/chrome/browser/net/metrics_network_client.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/test/histogram_tester.h"
 #include "net/base/net_errors.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // Dummy client to be registered as underlying client for the
 // MetricsNetworkClient.
 @interface MetricsMockClient : CRNForwardingNetworkClient
 @end
 
 @implementation MetricsMockClient
 
 - (void)didFailWithNSErrorCode:(NSInteger)nsErrorCode
                   netErrorCode:(int)netErrorCode {
 }
@@ skipping 41 matching lines @@
                      netErrorCode:net_error];
   // |net_error| is negative, the histogram reports the opposite value.
   histogram_tester_.ExpectUniqueSample(kHistogramName, -net_error, 1);
 }
 
 TEST_F(MetricsNetworkClientTest, HistogramUpdatedOnSuccess) {
   VerifyNoSamples();
   [client_ didFinishLoading];
   histogram_tester_.ExpectUniqueSample(kHistogramName, -net::OK, 1);
 }