Add CrosDisksClient

chrome/browser/chromeos/disks/disk_mount_manager.cc

+// Copyright (c) 2011 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/disks/disk_mount_manager.h"
+
+#include <map>
+#include <set>
+
+#include <sys/statvfs.h>
+
+#include "base/bind.h"
+#include "base/string_util.h"
+#include "chrome/browser/chromeos/dbus/dbus_thread_manager.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace chromeos {
+namespace disks {
+
+namespace {
+
+const char kDeviceNotFound[] = "Device could not be found";
+
+DiskMountManager* g_disk_mount_manager = NULL;
+
+// The DiskMountManager implementation.
+class DiskMountManagerImpl : public DiskMountManager {
+ public:
+  DiskMountManagerImpl() : weak_ptr_factory_(this) {
+    DBusThreadManager* dbus_thread_manager = DBusThreadManager::Get();
+    DCHECK(dbus_thread_manager);
+    cros_disks_client_ = dbus_thread_manager->GetCrosDisksClient();
+    DCHECK(cros_disks_client_);
+
+    cros_disks_client_->SetUpConnections(
+        base::Bind(&DiskMountManagerImpl::OnMountEvent,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&DiskMountManagerImpl::OnMountCompleted,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+
+  virtual ~DiskMountManagerImpl() {
+  }
+
+  // DiskMountManager override.
+  virtual void AddObserver(Observer* observer) OVERRIDE {
+    observers_.AddObserver(observer);
+  }
+
+  // DiskMountManager override.
+  virtual void RemoveObserver(Observer* observer) OVERRIDE {
+    observers_.RemoveObserver(observer);
+  }
+
+  // DiskMountManager override.
+  virtual void MountPath(const std::string& source_path,
+                         MountType type) OVERRIDE {
+    // Hidden and non-existent devices should not be mounted.
+    if (type == MOUNT_TYPE_DEVICE) {
+      DiskMap::const_iterator it = disks_.find(source_path);
+      if (it == disks_.end() || it->second->is_hidden()) {
+        OnMountCompleted(MOUNT_ERROR_INTERNAL, source_path, type, "");
+        return;
+      }
+    }
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    cros_disks_client_->Mount(
+        source_path,
+        type,
+        // When succeeds, OnMountCompleted will be called by
+        // "MountCompleted" signal instead.
+        base::Bind(&DoNothing),
+        base::Bind(&DiskMountManagerImpl::OnMountCompleted,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   MOUNT_ERROR_INTERNAL,
+                   source_path,
+                   type,
+                   ""));
+  }
+
+  // DiskMountManager override.
+  virtual void UnmountPath(const std::string& mount_path) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    cros_disks_client_->Unmount(mount_path,
+                                base::Bind(&DiskMountManagerImpl::OnUnmountPath,
+                                           weak_ptr_factory_.GetWeakPtr()),
+                                base::Bind(&DoNothing));
+  }
+
+  // DiskMountManager override.
+  virtual void GetSizeStatsOnFileThread(const std::string& mount_path,
+                                        size_t* total_size_kb,
+                                        size_t* remaining_size_kb) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+
+    uint64_t total_size_in_bytes = 0;
+    uint64_t remaining_size_in_bytes = 0;
+
+    struct statvfs stat = {};  // Zero-clear
+    if (statvfs(mount_path.c_str(), &stat) == 0) {
+      total_size_in_bytes =
+          static_cast<uint64_t>(stat.f_blocks) * stat.f_frsize;
+      remaining_size_in_bytes =
+          static_cast<uint64_t>(stat.f_bfree) * stat.f_frsize;
+    }
+    *total_size_kb = static_cast<size_t>(total_size_in_bytes / 1024);
+    *remaining_size_kb = static_cast<size_t>(remaining_size_in_bytes / 1024);
+  }
+
+  // DiskMountManager override.
+  virtual void FormatUnmountedDevice(const std::string& file_path) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    for (DiskMountManager::DiskMap::iterator it = disks_.begin();
+         it != disks_.end(); ++it) {
+      if (it->second->file_path() == file_path &&
+          !it->second->mount_path().empty()) {
+        LOG(ERROR) << "Device is still mounted: " << file_path;
+        OnFormatDevice(file_path, false);
+        return;
+      }
+    }
+    const char kFormatVFAT[] = "vfat";
+    cros_disks_client_->FormatDevice(
+        file_path,
+        kFormatVFAT,
+        base::Bind(&DiskMountManagerImpl::OnFormatDevice,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&DiskMountManagerImpl::OnFormatDevice,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   file_path,
+                   false));
+  }
+
+  // DiskMountManager override.
+  virtual void FormatMountedDevice(const std::string& mount_path) OVERRIDE {
+    Disk* disk = NULL;
+    for (DiskMountManager::DiskMap::iterator it = disks_.begin();
+         it != disks_.end(); ++it) {
+      if (it->second->mount_path() == mount_path) {
+        disk = it->second;
+        break;
+      }
+    }
+    if (!disk) {
+      LOG(ERROR) << "Device with this mount path not found: " << mount_path;
+      OnFormatDevice(mount_path, false);
+      return;
+    }
+    if (formatting_pending_.find(disk->device_path()) !=
+        formatting_pending_.end()) {
+      LOG(ERROR) << "Formatting is already pending: " << mount_path;
+      OnFormatDevice(mount_path, false);
+      return;
+    }
+    // Formatting process continues, after unmounting.
+    formatting_pending_[disk->device_path()] = disk->file_path();
+    UnmountPath(disk->mount_path());
+  }
+
+  // DiskMountManager override.
+  virtual void UnmountDeviceRecursive(
+      const std::string& device_path,
+      UnmountDeviceRecursiveCallbackType callback,
+      void* user_data) OVERRIDE {
+    bool success = true;
+    std::string error_message;
+    std::vector<std::string> devices_to_unmount;
+
+    // Get list of all devices to unmount.
+    int device_path_len = device_path.length();
+    for (DiskMap::iterator it = disks_.begin(); it != disks_.end(); ++it) {
+      if (!it->second->mount_path().empty() &&
+          strncmp(device_path.c_str(), it->second->device_path().c_str(),
+                  device_path_len) == 0) {
+        devices_to_unmount.push_back(it->second->mount_path());
+      }
+    }
+    // We should detect at least original device.
+    if (devices_to_unmount.empty()) {
+      if (disks_.find(device_path) == disks_.end()) {
+        success = false;
+        error_message = kDeviceNotFound;
+      } else {
+        // Nothing to unmount.
+        callback(user_data, true);
+        return;
+      }
+    }
+    if (success) {
+      // We will send the same callback data object to all Unmount calls and use
+      // it to syncronize callbacks.
+      UnmountDeviceRecursiveCallbackData* cb_data =
+          new UnmountDeviceRecursiveCallbackData(user_data, callback,
+                                                 devices_to_unmount.size());
+      for (size_t i = 0; i < devices_to_unmount.size(); ++i) {
+        cros_disks_client_->Unmount(
+            devices_to_unmount[i],
+            base::Bind(&DiskMountManagerImpl::OnUnmountDeviceRecursive,
+                       weak_ptr_factory_.GetWeakPtr(), cb_data, true),
+            base::Bind(&DiskMountManagerImpl::OnUnmountDeviceRecursive,
+                       weak_ptr_factory_.GetWeakPtr(),
+                       cb_data,
+                       false,
+                       devices_to_unmount[i]));
+      }
+    } else {
+      LOG(WARNING) << "Unmount recursive request failed for device "
+                   << device_path << ", with error: " << error_message;
+      callback(user_data, false);
+    }
+  }
+
+  // DiskMountManager override.
+  virtual void RequestMountInfoRefresh() OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    cros_disks_client_->EnumerateAutoMountableDevices(
+        base::Bind(&DiskMountManagerImpl::OnRequestMountInfo,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&DoNothing));
+  }
+
+  // DiskMountManager override.
+  const DiskMap& disks() const OVERRIDE { return disks_; }
+
+
+  // DiskMountManager override.
+  const MountPointMap& mount_points() const OVERRIDE { return mount_points_; }
+
+ private:
+  struct UnmountDeviceRecursiveCallbackData {
+    void* user_data;
+    UnmountDeviceRecursiveCallbackType callback;
+    size_t pending_callbacks_count;
+
+    UnmountDeviceRecursiveCallbackData(void* ud,
+                                       UnmountDeviceRecursiveCallbackType cb,
+                                       int count)
+        : user_data(ud),
+          callback(cb),
+          pending_callbacks_count(count) {
+    }
+  };
+
+  // Callback for UnmountDeviceRecursive.
+  void OnUnmountDeviceRecursive(UnmountDeviceRecursiveCallbackData* cb_data,
+                                bool success,
+                                const std::string& mount_path) {
+    if (success) {
+      // Do standard processing for Unmount event.
+      OnUnmountPath(mount_path);
+      LOG(INFO) << mount_path <<  " unmounted.";
+    }
+    // This is safe as long as all callbacks are called on the same thread as
+    // UnmountDeviceRecursive.
+    cb_data->pending_callbacks_count--;
+
+    if (cb_data->pending_callbacks_count == 0) {
+      cb_data->callback(cb_data->user_data, success);
+      delete cb_data;
+    }
+  }
+
+  // Callback to handle MountCompleted signal and Mount method call failure.
+  void OnMountCompleted(MountError error_code,
+                        const std::string& source_path,
+                        MountType mount_type,
+                        const std::string& mount_path) {
+    MountCondition mount_condition = MOUNT_CONDITION_NONE;
+    if (mount_type == MOUNT_TYPE_DEVICE) {
+      if (error_code == MOUNT_ERROR_UNKNOWN_FILESYSTEM)
+        mount_condition = MOUNT_CONDITION_UNKNOWN_FILESYSTEM;
+      if (error_code == MOUNT_ERROR_UNSUPORTED_FILESYSTEM)
+        mount_condition = MOUNT_CONDITION_UNSUPPORTED_FILESYSTEM;
+    }
+    const MountPointInfo mount_info(source_path, mount_path, mount_type,
+                                    mount_condition);
+
+    NotifyMountCompleted(MOUNTING, error_code, mount_info);
+
+    // If the device is corrupted but it's still possible to format it, it will
+    // be fake mounted.
+    if ((error_code == MOUNT_ERROR_NONE || mount_info.mount_condition) &&
+        mount_points_.find(mount_info.mount_path) == mount_points_.end()) {
+      mount_points_.insert(MountPointMap::value_type(mount_info.mount_path,
+                                                     mount_info));
+    }
+    if ((error_code == MOUNT_ERROR_NONE || mount_info.mount_condition) &&
+        mount_info.mount_type == MOUNT_TYPE_DEVICE &&
+        !mount_info.source_path.empty() &&
+        !mount_info.mount_path.empty()) {
+      DiskMap::iterator iter = disks_.find(mount_info.source_path);
+      if (iter == disks_.end()) {
+        // disk might have been removed by now?
+        return;
+      }
+      Disk* disk = iter->second;
+      DCHECK(disk);
+      disk->set_mount_path(mount_info.mount_path);
+      NotifyDiskStatusUpdate(MOUNT_DISK_MOUNTED, disk);
+    }
+  }
+
+  // Callback for UnmountPath.
+  void OnUnmountPath(const std::string& mount_path) {
+    MountPointMap::iterator mount_points_it = mount_points_.find(mount_path);
+    if (mount_points_it == mount_points_.end())
+      return;
+    // TODO(tbarzic): Add separate, PathUnmounted event to Observer.
+    NotifyMountCompleted(UNMOUNTING,
+                         MOUNT_ERROR_NONE,
+                         MountPointInfo(mount_points_it->second.source_path,
+                                        mount_points_it->second.mount_path,
+                                        mount_points_it->second.mount_type,
+                                        mount_points_it->second.mount_condition)
+                         );
+    std::string path(mount_points_it->second.source_path);
+    mount_points_.erase(mount_points_it);
+    DiskMap::iterator iter = disks_.find(path);
+    if (iter == disks_.end()) {
+      // disk might have been removed by now.
+      return;
+    }
+    Disk* disk = iter->second;
+    DCHECK(disk);
+    disk->clear_mount_path();
+    // Check if there is a formatting scheduled.
+    PathMap::iterator it = formatting_pending_.find(disk->device_path());
+    if (it != formatting_pending_.end()) {
+      const std::string& file_path = it->second;
+      formatting_pending_.erase(it);
+      FormatUnmountedDevice(file_path);
+    }
+  }
+
+  // Callback for FormatDevice.
+  void OnFormatDevice(const std::string& device_path, bool success) {
+    if (success) {
+      NotifyDeviceStatusUpdate(MOUNT_FORMATTING_STARTED, device_path);
+    } else {
+      NotifyDeviceStatusUpdate(MOUNT_FORMATTING_STARTED,
+                             std::string("!") + device_path);
+      LOG(WARNING) << "Format request failed for device " << device_path;
+    }
+  }
+
+  // Callbcak for GetDeviceProperties.
+  void OnGetDeviceProperties(const DiskInfo& disk_info) {
+    // TODO(zelidrag): Find a better way to filter these out before we
+    // fetch the properties:
+    // Ignore disks coming from the device we booted the system from.
+    if (disk_info.on_boot_device())
+      return;
+
+    LOG(WARNING) << "Found disk " << disk_info.device_path();
+    // Delete previous disk info for this path:
+    bool is_new = true;
+    DiskMap::iterator iter = disks_.find(disk_info.device_path());
+    if (iter != disks_.end()) {
+      delete iter->second;
+      disks_.erase(iter);
+      is_new = false;
+    }
+    Disk* disk = new Disk(disk_info.device_path(),
+                          disk_info.mount_path(),
+                          disk_info.system_path(),
+                          disk_info.file_path(),
+                          disk_info.label(),
+                          disk_info.drive_label(),
+                          FindSystemPathPrefix(disk_info.system_path()),
+                          disk_info.device_type(),
+                          disk_info.total_size_in_bytes(),
+                          disk_info.is_drive(),
+                          disk_info.is_read_only(),
+                          disk_info.has_media(),
+                          disk_info.on_boot_device(),
+                          disk_info.is_hidden());
+    disks_.insert(std::make_pair(disk_info.device_path(), disk));
+    NotifyDiskStatusUpdate(is_new ? MOUNT_DISK_ADDED : MOUNT_DISK_CHANGED,
+                           disk);
+  }
+
+  // Callbcak for RequestMountInfo.
+  void OnRequestMountInfo(const std::vector<std::string>& devices) {
+    std::set<std::string> current_device_set;
+    if (!devices.empty()) {
+      // Initiate properties fetch for all removable disks,
+      for (size_t i = 0; i < devices.size(); i++) {
+        current_device_set.insert(devices[i]);
+        // Initiate disk property retrieval for each relevant device path.
+        cros_disks_client_->GetDeviceProperties(
+            devices[i],
+            base::Bind(&DiskMountManagerImpl::OnGetDeviceProperties,
+                       weak_ptr_factory_.GetWeakPtr()),
+            base::Bind(&DoNothing));
+      }
+    }
+    // Search and remove disks that are no longer present.
+    for (DiskMap::iterator iter = disks_.begin(); iter != disks_.end(); ) {
+      if (current_device_set.find(iter->first) == current_device_set.end()) {
+        Disk* disk = iter->second;
+        NotifyDiskStatusUpdate(MOUNT_DISK_REMOVED, disk);
+        delete iter->second;
+        disks_.erase(iter++);
+      } else {
+        ++iter;
+      }
+    }
+  }
+
+  // Callback to handle mount event signals.
+  void OnMountEvent(MountEventType event, std::string device_path) {
+    DiskMountManagerEventType type = MOUNT_DEVICE_ADDED;
+    switch (event) {
+      case DISK_ADDED: {
+        cros_disks_client_->GetDeviceProperties(
+            device_path,
+            base::Bind(&DiskMountManagerImpl::OnGetDeviceProperties,
+                       weak_ptr_factory_.GetWeakPtr()),
+            base::Bind(&DoNothing));
+        return;
+      }
+      case DISK_REMOVED: {
+        // Search and remove disks that are no longer present.
+        DiskMountManager::DiskMap::iterator iter = disks_.find(device_path);
+        if (iter != disks_.end()) {
+          Disk* disk = iter->second;
+          NotifyDiskStatusUpdate(MOUNT_DISK_REMOVED, disk);
+          delete iter->second;
+          disks_.erase(iter);
+        }
+        return;
+      }
+      case DEVICE_ADDED: {
+        type = MOUNT_DEVICE_ADDED;
+        system_path_prefixes_.insert(device_path);
+        break;
+      }
+      case DEVICE_REMOVED: {
+        type = MOUNT_DEVICE_REMOVED;
+        system_path_prefixes_.erase(device_path);
+        break;
+      }
+      case DEVICE_SCANNED: {
+        type = MOUNT_DEVICE_SCANNED;
+        break;
+      }
+      case FORMATTING_FINISHED: {
+        // FORMATTING_FINISHED actually returns file path instead of device
+        // path.
+        device_path = FilePathToDevicePath(device_path);
+        if (device_path.empty()) {
+          LOG(ERROR) << "Error while handling disks metadata. Cannot find "
+                     << "device that is being formatted.";
+          return;
+        }
+        type = MOUNT_FORMATTING_FINISHED;
+        break;
+      }
+      default: {
+        LOG(ERROR) << "Unknown event: " << event;
+        return;
+      }
+    }
+    NotifyDeviceStatusUpdate(type, device_path);
+  }
+
+  // Notifies all observers about disk status update.
+  void NotifyDiskStatusUpdate(DiskMountManagerEventType event,
+                              const Disk* disk) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    FOR_EACH_OBSERVER(Observer, observers_, DiskChanged(event, disk));
+  }
+
+  // Notifies all observers about device status update.
+  void NotifyDeviceStatusUpdate(DiskMountManagerEventType event,
+                                const std::string& device_path) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    FOR_EACH_OBSERVER(Observer, observers_, DeviceChanged(event, device_path));
+  }
+
+  // Notifies all observers about mount completion.
+  void NotifyMountCompleted(MountEvent event_type,
+                            MountError error_code,
+                            const MountPointInfo& mount_info) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    FOR_EACH_OBSERVER(Observer, observers_,
+                      MountCompleted(event_type, error_code, mount_info));
+  }
+
+  // Converts file path to device path.
+  std::string FilePathToDevicePath(const std::string& file_path) {
+    // TODO(hashimoto): Refactor error handling code like here.
+    // Appending "!" is not the best way to indicate error.  This kind of trick
+    // also makes it difficult to simplify the code paths.  crosbug.com/22972
+    const int failed = StartsWithASCII(file_path, "!", true);
+    for (DiskMountManager::DiskMap::iterator it = disks_.begin();
+         it != disks_.end(); ++it) {
+      // Skip the leading '!' on the failure case.
+      if (it->second->file_path() == file_path.substr(failed)) {
+        if (failed)
+          return std::string("!") + it->second->device_path();
+        else
+          return it->second->device_path();
+      }
+    }
+    return "";
+  }
+
+  // Finds system path prefix from |system_path|.
+  const std::string& FindSystemPathPrefix(const std::string& system_path) {
+    if (system_path.empty())
+      return EmptyString();
+    for (SystemPathPrefixSet::const_iterator it = system_path_prefixes_.begin();
+         it != system_path_prefixes_.end();
+         ++it) {
+      const std::string& prefix = *it;
+      if (StartsWithASCII(system_path, prefix, true))
+        return prefix;
+    }
+    return EmptyString();
+  }
+
+  // A function to be used as an empty callback.
+  static void DoNothing() {
+  }
+
+  // Mount event change observers.
+  ObserverList<Observer> observers_;
+
+  CrosDisksClient* cros_disks_client_;
+
+  // The list of disks found.
+  DiskMountManager::DiskMap disks_;
+
+  DiskMountManager::MountPointMap mount_points_;
+
+  typedef std::set<std::string> SystemPathPrefixSet;
+  SystemPathPrefixSet system_path_prefixes_;
+
+  // A map from device path (e.g. /sys/devices/pci0000:00/.../sdb/sdb1)) to file
+  // path (e.g. /dev/sdb).
+  // Devices in this map are supposed to be formatted, but are currently waiting
+  // to be unmounted. When device is in this map, the formatting process HAVEN'T
+  // started yet.
+  typedef std::map<std::string, std::string> PathMap;
+  PathMap formatting_pending_;
+
+  base::WeakPtrFactory<DiskMountManagerImpl> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DiskMountManagerImpl);
+};
+
+} // namespace
+
+DiskMountManager::Disk::Disk(const std::string& device_path,
+                             const std::string& mount_path,
+                             const std::string& system_path,
+                             const std::string& file_path,
+                             const std::string& device_label,
+                             const std::string& drive_label,
+                             const std::string& system_path_prefix,
+                             DeviceType device_type,
+                             uint64 total_size_in_bytes,
+                             bool is_parent,
+                             bool is_read_only,
+                             bool has_media,
+                             bool on_boot_device,
+                             bool is_hidden)
+    : device_path_(device_path),
+      mount_path_(mount_path),
+      system_path_(system_path),
+      file_path_(file_path),
+      device_label_(device_label),
+      drive_label_(drive_label),
+      system_path_prefix_(system_path_prefix),
+      device_type_(device_type),
+      total_size_in_bytes_(total_size_in_bytes),
+      is_parent_(is_parent),
+      is_read_only_(is_read_only),
+      has_media_(has_media),
+      on_boot_device_(on_boot_device),
+      is_hidden_(is_hidden) {
+}
+
+DiskMountManager::Disk::~Disk() {}
+
+// static
+std::string DiskMountManager::MountTypeToString(MountType type) {
+  switch (type) {
+    case MOUNT_TYPE_DEVICE:
+      return "device";
+    case MOUNT_TYPE_ARCHIVE:
+      return "file";
+    case MOUNT_TYPE_NETWORK_STORAGE:
+      return "network";
+    case MOUNT_TYPE_INVALID:
+      return "invalid";
+    default:
+      NOTREACHED();
+  }
+  return "";
+}
+
+// static
+std::string DiskMountManager::MountConditionToString(MountCondition condition) {
+  switch (condition) {
+    case MOUNT_CONDITION_NONE:
+      return "";
+    case MOUNT_CONDITION_UNKNOWN_FILESYSTEM:
+      return "unknown_filesystem";
+    case MOUNT_CONDITION_UNSUPPORTED_FILESYSTEM:
+      return "unsupported_filesystem";
+    default:
+      NOTREACHED();
+  }
+  return "";
+}
+
+// static
+MountType DiskMountManager::MountTypeFromString(const std::string& type_str) {
+  if (type_str == "device")
+    return MOUNT_TYPE_DEVICE;
+  else if (type_str == "network")
+    return MOUNT_TYPE_NETWORK_STORAGE;
+  else if (type_str == "file")
+    return MOUNT_TYPE_ARCHIVE;
+  else
+    return MOUNT_TYPE_INVALID;
+}
+
+// static
+void DiskMountManager::Initialize() {
+  VLOG(1) << "DiskMountManager::Initialize";
+  DCHECK(!g_disk_mount_manager);
+  g_disk_mount_manager = new DiskMountManagerImpl();
+  DCHECK(g_disk_mount_manager);
+}
+
+// static
+void DiskMountManager::Shutdown() {
+  VLOG(1) << "DiskMountManager::Shutdown";
+  if (g_disk_mount_manager) {
+    delete g_disk_mount_manager;
+    g_disk_mount_manager = NULL;
+  }
+}
+
+// static
+DiskMountManager* DiskMountManager::GetInstance() {
+  return g_disk_mount_manager;
+}
+
+}  // namespace disks
+}  // namespace chromeos