Use base::StringPairs where appropriate from src/extensions

extensions/common/permissions/permission_message_util.cc

 // 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 "extensions/common/permissions/permission_message_util.h"
 
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
 #include "extensions/common/permissions/permission_message.h"
 #include "extensions/common/permissions/permission_set.h"
 #include "extensions/common/url_pattern_set.h"
 #include "grit/extensions_strings.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "url/url_constants.h"
 
 using extensions::PermissionMessage;
@@ skipping 67 matching lines @@
           kMessagesList[arraysize(kMessagesList) - 1].second),
       details);
 }
 
 std::set<std::string> GetDistinctHosts(const URLPatternSet& host_patterns,
                                        bool include_rcd,
                                        bool exclude_file_scheme) {
   // Use a vector to preserve order (also faster than a map on small sets).
   // Each item is a host split into two parts: host without RCDs and
   // current best RCD.
-  typedef std::vector<std::pair<std::string, std::string> > HostVector;
+  typedef base::StringPairs HostVector;
   HostVector hosts_best_rcd;
   for (URLPatternSet::const_iterator i = host_patterns.begin();
        i != host_patterns.end();
        ++i) {
     if (exclude_file_scheme && i->scheme() == url::kFileScheme)
       continue;
 
     std::string host = i->host();
 
     // Add the subdomain wildcard back to the host, if necessary.
@@ skipping 30 matching lines @@
   // Build up the final vector by concatenating hosts and RCDs.
   std::set<std::string> distinct_hosts;
   for (HostVector::iterator it = hosts_best_rcd.begin();
        it != hosts_best_rcd.end();
        ++it)
     distinct_hosts.insert(it->first + it->second);
   return distinct_hosts;
 }
 
 }  // namespace permission_message_util