Reduce memory use of GetLevenshteinDistance() by almost 50%

components/ssl_errors/error_classification.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_SSL_ERRORS_ERROR_CLASSIFICATION_H_
 #define COMPONENTS_SSL_ERRORS_ERROR_CLASSIFICATION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 45 matching lines @@
 // absence of the single-label prefix "www". E.g.: (The first domain
 // is hostname and the second domain is a DNS name in the certificate)
 //     www.example.com ~ example.com -> true
 //     example.com ~ www.example.com -> true
 //     www.food.example.com ~ example.com -> false
 //     mail.example.com ~ example.com -> false
 bool GetWWWSubDomainMatch(const GURL& request_url,
                           const std::vector<std::string>& dns_names,
                           std::string* www_match_host_name);
 
+// Exposed for testing.
+size_t GetLevenshteinDistance(const std::string& str1, const std::string& str2);

[felt, 2016/02/11 00:10:42]

Could you move this into the "helper methods" section below?

+
 // Method for recording results. -----------------------------------------------
 
 void RecordUMAStatistics(bool overridable,
                          const base::Time& current_time,
                          const GURL& request_url,
                          int cert_error,
                          const net::X509Certificate& cert);
 
 // Helper methods for classification. ------------------------------------------
 
@@ skipping 20 matching lines @@
 // Returns true if any of the |potential_children| is a subdomain of the
 // |parent|. The inverse case should be treated carefully as this is most
 // likely a MITM attack. We don't want foo.appspot.com to be able to MITM for
 // appspot.com.
 bool AnyNamesUnderName(const std::vector<HostnameTokens>& potential_children,
                        const HostnameTokens& parent);
 
 }  // namespace ssl_errors
 
 #endif  // COMPONENTS_SSL_ERRORS_ERROR_CLASSIFICATION_H_