Update the remaining references to sys_string_conversions.h to its new location.

webkit/glue/simple_webmimeregistry_impl.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 "webkit/glue/simple_webmimeregistry_impl.h"
 
 #include "base/string_util.h"
-#include "base/sys_string_conversions.h"
+#include "base/strings/sys_string_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "media/filters/stream_parser_factory.h"
 #include "net/base/mime_util.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebString.h"
 #include "webkit/base/file_path_string_conversions.h"
 #include "webkit/media/crypto/key_systems.h"
 
 using WebKit::WebString;
 using WebKit::WebMimeRegistry;
 
@@ skipping 133 matching lines @@
 
 WebString SimpleWebMimeRegistryImpl::preferredExtensionForMIMEType(
     const WebString& mime_type) {
   base::FilePath::StringType file_extension;
   net::GetPreferredExtensionForMimeType(ToASCIIOrEmpty(mime_type),
                                         &file_extension);
   return webkit_base::FilePathStringToWebString(file_extension);
 }
 
 }  // namespace webkit_glue