Use a direct include of strings headers in chrome/common/, part 1.

chrome/common/cloud_print/cloud_print_helpers.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 "chrome/common/cloud_print/cloud_print_helpers.h"
 
 #include "base/json/json_reader.h"
 #include "base/logging.h"
 #include "base/md5.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/rand_util.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/values.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/cloud_print/cloud_print_constants.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/mime_util.h"
 
 namespace cloud_print {
 
 namespace {
@@ skipping 208 matching lines @@
   net::AddMultipartValueForUpload(kPrinterTagValue, tags_hash_msg,
       mime_boundary, std::string(), &post_data);
   return post_data;
 }
 
 std::string GetCloudPrintAuthHeader(const std::string& auth_token) {
   return base::StringPrintf("Authorization: OAuth %s", auth_token.c_str());
 }
 
 }  // namespace cloud_print