Use a direct include of strings headers in extensions/, google_apis/, gpu/.

extensions/common/id_util.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 "extensions/common/id_util.h"
 
 #include "base/files/file_path.h"
-#include "base/string_number_conversions.h"
-#include "base/string_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "crypto/sha2.h"
 
 namespace {
 
 // Converts a normal hexadecimal string into the alphabet used by extensions.
 // We use the characters 'a'-'p' instead of '0'-'f' to avoid ever having a
 // completely numeric host, since some software interprets that as an IP
 // address.
 static void ConvertHexadecimalToIDAlphabet(std::string* id) {
   for (size_t i = 0; i < id->size(); ++i) {
@@ skipping 44 matching lines @@
     path_str[0] += ('A' - 'a');
 
   return base::FilePath(path_str);
 #else
   return path;
 #endif
 }
 
 }  // namespace id_util
 }  // namespace extensions