Use base::StringPairs where appropriate from src/chrome/browser

chrome/browser/extensions/api/identity/gaia_web_auth_flow.cc

 // Copyright (c) 2013 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 "chrome/browser/extensions/api/identity/gaia_web_auth_flow.h"
 
 #include "base/debug/trace_event.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ skipping 153 matching lines @@
     web_flow_.release()->DetachDelegateAndDelete();
 
     std::string fragment = url.GetContent().substr(
         redirect_path_prefix_.length(), std::string::npos);
     base::StringPairs pairs;
     base::SplitStringIntoKeyValuePairs(fragment, '=', '&', &pairs);
     std::string access_token;
     std::string error;
     std::string expiration;
 
-    for (std::vector<std::pair<std::string, std::string> >::iterator
-             it = pairs.begin();
+    for (base::StringPairs::iterator it = pairs.begin();
          it != pairs.end();
          ++it) {
       if (it->first == kOAuth2RedirectAccessTokenKey)
         access_token = it->second;
       else if (it->first == kOAuth2RedirectErrorKey)
         error = it->second;
       else if (it->first == kOAuth2ExpiresInKey)
         expiration = it->second;
     }
 
@@ skipping 27 matching lines @@
 }
 
 scoped_ptr<WebAuthFlow> GaiaWebAuthFlow::CreateWebAuthFlow(GURL url) {
   return scoped_ptr<WebAuthFlow>(new WebAuthFlow(this,
                                                  profile_,
                                                  url,
                                                  WebAuthFlow::INTERACTIVE));
 }
 
 }  // namespace extensions