[fsp] Add throttling for number of opened files.

chrome/browser/chromeos/file_system_provider/provided_file_system_info.cc

 // Copyright 2014 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/chromeos/file_system_provider/provided_file_system_info.h"
+#include "base/logging.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
-MountOptions::MountOptions() : writable(false), supports_notify_tag(false) {
+MountOptions::MountOptions()
+    : writable(false), supports_notify_tag(false), opened_files_limit(0) {
 }
 
 MountOptions::MountOptions(const std::string& file_system_id,
                            const std::string& display_name)
     : file_system_id(file_system_id),
       display_name(display_name),
       writable(false),
-      supports_notify_tag(false) {
+      supports_notify_tag(false),
+      opened_files_limit(0) {
 }
 
 ProvidedFileSystemInfo::ProvidedFileSystemInfo()
     : writable_(false), supports_notify_tag_(false) {
 }
 
 ProvidedFileSystemInfo::ProvidedFileSystemInfo(
     const std::string& extension_id,
     const MountOptions& mount_options,
     const base::FilePath& mount_path)
     : extension_id_(extension_id),
       file_system_id_(mount_options.file_system_id),
       display_name_(mount_options.display_name),
       writable_(mount_options.writable),
       supports_notify_tag_(mount_options.supports_notify_tag),
+      opened_files_limit_(mount_options.opened_files_limit),
       mount_path_(mount_path) {
+  DCHECK_LE(0, mount_options.opened_files_limit);
 }
 
 ProvidedFileSystemInfo::~ProvidedFileSystemInfo() {}
 
 }  // namespace file_system_provider
 }  // namespace chromeos