[ObjC ARC] Converts ios/net to ARC.

ios/net/clients/crn_forwarding_network_client_factory.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.
 
 #import "ios/net/clients/crn_forwarding_network_client_factory.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/memory/weak_ptr.h"
 #import "ios/net/clients/crn_forwarding_network_client.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @implementation CRNForwardingNetworkClientFactory
 
 // Init just sanity checks that the factory class has sane ordering rules.
 - (instancetype)init {
   if ((self = [super init])) {
     // Type checks.
     DCHECK(![[self class] mustApplyBefore] ||
            [[[self class] mustApplyBefore]
                isSubclassOfClass:[CRNForwardingNetworkClientFactory class]]);
     DCHECK(![[self class] mustApplyAfter] ||
@@ skipping 72 matching lines @@
     result = NSOrderedAscending;
   }
   if ([[self class] mustApplyAfter] == [factory class] ||
       [[factory class] mustApplyBefore] == [self class]) {
     result = NSOrderedDescending;
   }
   return result;
 }
 
 @end