[Cleanup] Remove StringPrintf from global namespace

google_apis/gaia/oauth2_revocation_fetcher.cc

 // Copyright (c) 2012 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 "google_apis/gaia/oauth2_revocation_fetcher.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 136 matching lines @@
 }
 
 // static
 GURL OAuth2RevocationFetcher::MakeRevocationUrl() {
   return GURL(kOAuth2RevokeTokenURL);
 }
 
 // static
 std::string OAuth2RevocationFetcher::MakeRevocationHeader(
     const std::string& access_token) {
-  return StringPrintf(kAuthorizationHeaderFormat, access_token.c_str());
+  return base::StringPrintf(kAuthorizationHeaderFormat, access_token.c_str());
 }
 
 // static
 std::string OAuth2RevocationFetcher::MakeRevocationBody(
     const std::string& client_id,
     const std::string& origin) {
   std::string enc_client_id = net::EscapeUrlEncodedData(client_id, true);
   std::string enc_origin = net::EscapeUrlEncodedData(origin, true);
-  return StringPrintf(
+  return base::StringPrintf(
       kRevocationBodyFormat,
       enc_client_id.c_str(),
       enc_origin.c_str());
 }