Change other usages of .size() to .empty() when applicable.

net/base/x509_cert_types_mac.cc

 // Copyright (c) 2010 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 "net/base/x509_cert_types.h"
 
 #include <CoreServices/CoreServices.h>
 #include <Security/Security.h>
 #include <Security/SecAsn1Coder.h>
 
@@ skipping 132 matching lines @@
       break;
     }
   }
 }
 
 // Stores the first string of the vector, if any, to *single_value.
 void SetSingle(const std::vector<std::string>& values,
                std::string* single_value) {
   // We don't expect to have more than one CN, L, S, and C.
   LOG_IF(WARNING, values.size() > 1) << "Didn't expect multiple values";
-  if (values.size() > 0)
+  if (!values.empty())
     *single_value = values[0];
 }
 
 bool match(const std::string& str, const std::string& against) {
   // TODO(snej): Use the full matching rules specified in RFC 5280 sec. 7.1
   // including trimming and case-folding: <http://www.ietf.org/rfc/rfc5280.txt>.
   return against == str;
 }
 
 bool match(const std::vector<std::string>& rdn1,
@@ skipping 138 matching lines @@
       match(locality_name, against.locality_name) &&
       match(state_or_province_name, against.state_or_province_name) &&
       match(country_name, against.country_name) &&
       match(street_addresses, against.street_addresses) &&
       match(organization_names, against.organization_names) &&
       match(organization_unit_names, against.organization_unit_names) &&
       match(domain_components, against.domain_components);
 }
 
 }  // namespace net