Reland 2:Geolocation: move from content/browser to device/

content/browser/geolocation/wifi_data_provider_win.cc

Index: content/browser/geolocation/wifi_data_provider_win.cc
diff --git a/content/browser/geolocation/wifi_data_provider_win.cc b/content/browser/geolocation/wifi_data_provider_win.cc
deleted file mode 100644
index c5eca3d6f20298508351650a8c204bec0f14c337..0000000000000000000000000000000000000000
--- a/content/browser/geolocation/wifi_data_provider_win.cc
+++ /dev/null
@@ -1,643 +0,0 @@
-// Copyright (c) 2010 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.
-
-// Windows Vista uses the Native Wifi (WLAN) API for accessing WiFi cards. See
-// http://msdn.microsoft.com/en-us/library/ms705945(VS.85).aspx. Windows XP
-// Service Pack 3 (and Windows XP Service Pack 2, if upgraded with a hot fix)
-// also support a limited version of the WLAN API. See
-// http://msdn.microsoft.com/en-us/library/bb204766.aspx. The WLAN API uses
-// wlanapi.h, which is not part of the SDK used by Gears, so is replicated
-// locally using data from the MSDN.
-//
-// Windows XP from Service Pack 2 onwards supports the Wireless Zero
-// Configuration (WZC) programming interface. See
-// http://msdn.microsoft.com/en-us/library/ms706587(VS.85).aspx.
-//
-// The MSDN recommends that one use the WLAN API where available, and WZC
-// otherwise.
-//
-// However, it seems that WZC fails for some wireless cards. Also, WLAN seems
-// not to work on XP SP3. So we use WLAN on Vista, and use NDIS directly
-// otherwise.
-
-#include "content/browser/geolocation/wifi_data_provider_win.h"
-
-#include <windows.h>
-#include <winioctl.h>
-#include <wlanapi.h>
-
-#include "base/memory/free_deleter.h"
-#include "base/metrics/histogram.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/windows_version.h"
-#include "content/browser/geolocation/wifi_data_provider_common.h"
-#include "content/browser/geolocation/wifi_data_provider_common_win.h"
-#include "content/browser/geolocation/wifi_data_provider_manager.h"
-
-// Taken from ndis.h for WinCE.
-#define NDIS_STATUS_INVALID_LENGTH   ((NDIS_STATUS)0xC0010014L)
-#define NDIS_STATUS_BUFFER_TOO_SHORT ((NDIS_STATUS)0xC0010016L)
-
-namespace content {
-namespace {
-// The limits on the size of the buffer used for the OID query.
-const int kInitialBufferSize = 2 << 12;  // Good for about 50 APs.
-const int kMaximumBufferSize = 2 << 20;  // 2MB
-
-// Length for generic string buffers passed to Windows APIs.
-const int kStringLength = 512;
-
-// The time periods, in milliseconds, between successive polls of the wifi data.
-const int kDefaultPollingInterval = 10000;  // 10s
-const int kNoChangePollingInterval = 120000;  // 2 mins
-const int kTwoNoChangePollingInterval = 600000;  // 10 mins
-const int kNoWifiPollingIntervalMilliseconds = 20 * 1000; // 20s
-
-// WlanOpenHandle
-typedef DWORD (WINAPI* WlanOpenHandleFunction)(DWORD dwClientVersion,
-                                               PVOID pReserved,
-                                               PDWORD pdwNegotiatedVersion,
-                                               PHANDLE phClientHandle);
-
-// WlanEnumInterfaces
-typedef DWORD (WINAPI* WlanEnumInterfacesFunction)(
-    HANDLE hClientHandle,
-    PVOID pReserved,
-    PWLAN_INTERFACE_INFO_LIST* ppInterfaceList);
-
-// WlanGetNetworkBssList
-typedef DWORD (WINAPI* WlanGetNetworkBssListFunction)(
-    HANDLE hClientHandle,
-    const GUID* pInterfaceGuid,
-    const  PDOT11_SSID pDot11Ssid,
-    DOT11_BSS_TYPE dot11BssType,
-    BOOL bSecurityEnabled,
-    PVOID pReserved,
-    PWLAN_BSS_LIST* ppWlanBssList
-);
-
-// WlanFreeMemory
-typedef VOID (WINAPI* WlanFreeMemoryFunction)(PVOID pMemory);
-
-// WlanCloseHandle
-typedef DWORD (WINAPI* WlanCloseHandleFunction)(HANDLE hClientHandle,
-                                                PVOID pReserved);
-
-
-// Local classes and functions
-class WindowsWlanApi : public WifiDataProviderCommon::WlanApiInterface {
- public:
-  ~WindowsWlanApi() override;
-  // Factory function. Will return NULL if this API is unavailable.
-  static WindowsWlanApi* Create();
-
-  // WlanApiInterface
-  bool GetAccessPointData(WifiData::AccessPointDataSet* data) override;
-
- private:
-  // Takes ownership of the library handle.
-  explicit WindowsWlanApi(HINSTANCE library);
-
-  // Loads the required functions from the DLL.
-  void GetWLANFunctions(HINSTANCE wlan_library);
-  int GetInterfaceDataWLAN(HANDLE wlan_handle,
-                           const GUID& interface_id,
-                           WifiData::AccessPointDataSet* data);
-
-  // Logs number of detected wlan interfaces.
-  static void LogWlanInterfaceCount(int count);
-
-  // Handle to the wlanapi.dll library.
-  HINSTANCE library_;
-
-  // Function pointers for WLAN
-  WlanOpenHandleFunction WlanOpenHandle_function_;
-  WlanEnumInterfacesFunction WlanEnumInterfaces_function_;
-  WlanGetNetworkBssListFunction WlanGetNetworkBssList_function_;
-  WlanFreeMemoryFunction WlanFreeMemory_function_;
-  WlanCloseHandleFunction WlanCloseHandle_function_;
-};
-
-class WindowsNdisApi : public WifiDataProviderCommon::WlanApiInterface {
- public:
-  ~WindowsNdisApi() override;
-  static WindowsNdisApi* Create();
-
-  // WlanApiInterface
-  bool GetAccessPointData(WifiData::AccessPointDataSet* data) override;
-
- private:
-  static bool GetInterfacesNDIS(
-      std::vector<base::string16>* interface_service_names_out);
-
-  // Swaps in content of the vector passed
-  explicit WindowsNdisApi(std::vector<base::string16>* interface_service_names);
-
-  bool GetInterfaceDataNDIS(HANDLE adapter_handle,
-                            WifiData::AccessPointDataSet* data);
-  // NDIS variables.
-  std::vector<base::string16> interface_service_names_;
-
-  // Remembers scan result buffer size across calls.
-  int oid_buffer_size_;
-};
-
-// Extracts data for an access point and converts to Gears format.
-bool GetNetworkData(const WLAN_BSS_ENTRY& bss_entry,
-                    AccessPointData* access_point_data);
-bool UndefineDosDevice(const base::string16& device_name);
-bool DefineDosDeviceIfNotExists(const base::string16& device_name);
-HANDLE GetFileHandle(const base::string16& device_name);
-// Makes the OID query and returns a Windows API error code.
-int PerformQuery(HANDLE adapter_handle,
-                 BYTE* buffer,
-                 DWORD buffer_size,
-                 DWORD* bytes_out);
-bool ResizeBuffer(int requested_size,
-                  std::unique_ptr<BYTE, base::FreeDeleter>* buffer);
-// Gets the system directory and appends a trailing slash if not already
-// present.
-bool GetSystemDirectory(base::string16* path);
-}  // namespace
-
-WifiDataProvider* WifiDataProviderManager::DefaultFactoryFunction() {
-  return new WifiDataProviderWin();
-}
-
-WifiDataProviderWin::WifiDataProviderWin() {
-}
-
-WifiDataProviderWin::~WifiDataProviderWin() {
-}
-
-WifiDataProviderCommon::WlanApiInterface* WifiDataProviderWin::NewWlanApi() {
-  // Use the WLAN interface if we're on Vista and if it's available. Otherwise,
-  // use NDIS.
-  WlanApiInterface* api = WindowsWlanApi::Create();
-  if (api) {
-    return api;
-  }
-  return WindowsNdisApi::Create();
-}
-
-WifiPollingPolicy* WifiDataProviderWin::NewPollingPolicy() {
-  return new GenericWifiPollingPolicy<kDefaultPollingInterval,
-                                      kNoChangePollingInterval,
-                                      kTwoNoChangePollingInterval,
-                                      kNoWifiPollingIntervalMilliseconds>;
-}
-
-// Local classes and functions
-namespace {
-
-// WindowsWlanApi
-WindowsWlanApi::WindowsWlanApi(HINSTANCE library)
-    : library_(library) {
-  GetWLANFunctions(library_);
-}
-
-WindowsWlanApi::~WindowsWlanApi() {
-  FreeLibrary(library_);
-}
-
-WindowsWlanApi* WindowsWlanApi::Create() {
-  if (base::win::GetVersion() < base::win::VERSION_VISTA)
-    return NULL;
-  // We use an absolute path to load the DLL to avoid DLL preloading attacks.
-  base::string16 system_directory;
-  if (!GetSystemDirectory(&system_directory)) {
-    return NULL;
-  }
-  DCHECK(!system_directory.empty());
-  base::string16 dll_path = system_directory + L"wlanapi.dll";
-  HINSTANCE library = LoadLibraryEx(dll_path.c_str(),
-                                    NULL,
-                                    LOAD_WITH_ALTERED_SEARCH_PATH);
-  if (!library) {
-    return NULL;
-  }
-  return new WindowsWlanApi(library);
-}
-
-void WindowsWlanApi::GetWLANFunctions(HINSTANCE wlan_library) {
-  DCHECK(wlan_library);
-  WlanOpenHandle_function_ = reinterpret_cast<WlanOpenHandleFunction>(
-      GetProcAddress(wlan_library, "WlanOpenHandle"));
-  WlanEnumInterfaces_function_ = reinterpret_cast<WlanEnumInterfacesFunction>(
-      GetProcAddress(wlan_library, "WlanEnumInterfaces"));
-  WlanGetNetworkBssList_function_ =
-      reinterpret_cast<WlanGetNetworkBssListFunction>(
-      GetProcAddress(wlan_library, "WlanGetNetworkBssList"));
-  WlanFreeMemory_function_ = reinterpret_cast<WlanFreeMemoryFunction>(
-      GetProcAddress(wlan_library, "WlanFreeMemory"));
-  WlanCloseHandle_function_ = reinterpret_cast<WlanCloseHandleFunction>(
-      GetProcAddress(wlan_library, "WlanCloseHandle"));
-  DCHECK(WlanOpenHandle_function_ &&
-         WlanEnumInterfaces_function_ &&
-         WlanGetNetworkBssList_function_ &&
-         WlanFreeMemory_function_ &&
-         WlanCloseHandle_function_);
-}
-
-void WindowsWlanApi::LogWlanInterfaceCount(int count) {
-  UMA_HISTOGRAM_CUSTOM_COUNTS(
-      "Net.Wifi.InterfaceCount",
-      count,
-      1,
-      5,
-      6);
-}
-
-bool WindowsWlanApi::GetAccessPointData(
-    WifiData::AccessPointDataSet* data) {
-  DCHECK(data);
-
-  // Get the handle to the WLAN API.
-  DWORD negotiated_version;
-  HANDLE wlan_handle = NULL;
-  // We could be executing on either Windows XP or Windows Vista, so use the
-  // lower version of the client WLAN API. It seems that the negotiated version
-  // is the Vista version irrespective of what we pass!
-  static const int kXpWlanClientVersion = 1;
-  if ((*WlanOpenHandle_function_)(kXpWlanClientVersion,
-                                  NULL,
-                                  &negotiated_version,
-                                  &wlan_handle) != ERROR_SUCCESS) {
-    LogWlanInterfaceCount(0);
-    return false;
-  }
-  DCHECK(wlan_handle);
-
-  // Get the list of interfaces. WlanEnumInterfaces allocates interface_list.
-  WLAN_INTERFACE_INFO_LIST* interface_list = NULL;
-  if ((*WlanEnumInterfaces_function_)(wlan_handle, NULL, &interface_list) !=
-      ERROR_SUCCESS) {
-    LogWlanInterfaceCount(0);
-    return false;
-  }
-  DCHECK(interface_list);
-
-  LogWlanInterfaceCount(interface_list->dwNumberOfItems);
-
-  // Go through the list of interfaces and get the data for each.
-  for (int i = 0; i < static_cast<int>(interface_list->dwNumberOfItems); ++i) {
-    // Skip any interface that is midway through association; the
-    // WlanGetNetworkBssList function call is known to hang indefinitely
-    // when it's in this state. http://crbug.com/39300
-    if (interface_list->InterfaceInfo[i].isState ==
-        wlan_interface_state_associating) {
-      LOG(WARNING) << "Skipping wifi scan on adapter " << i << " ("
-                   << interface_list->InterfaceInfo[i].strInterfaceDescription
-                   << ") in 'associating' state. Repeated occurrences "
-                      "indicates a non-responding adapter.";
-      continue;
-    }
-    GetInterfaceDataWLAN(wlan_handle,
-                         interface_list->InterfaceInfo[i].InterfaceGuid,
-                         data);
-  }
-
-  // Free interface_list.
-  (*WlanFreeMemory_function_)(interface_list);
-
-  // Close the handle.
-  if ((*WlanCloseHandle_function_)(wlan_handle, NULL) != ERROR_SUCCESS) {
-    return false;
-  }
-
-  return true;
-}
-
-// Appends the data for a single interface to the data vector. Returns the
-// number of access points found, or -1 on error.
-int WindowsWlanApi::GetInterfaceDataWLAN(
-    const HANDLE wlan_handle,
-    const GUID& interface_id,
-    WifiData::AccessPointDataSet* data) {
-  DCHECK(data);
-
-  const base::TimeTicks start_time = base::TimeTicks::Now();
-
-  // WlanGetNetworkBssList allocates bss_list.
-  WLAN_BSS_LIST* bss_list = NULL;
-  if ((*WlanGetNetworkBssList_function_)(wlan_handle,
-                                         &interface_id,
-                                         NULL,   // Use all SSIDs.
-                                         dot11_BSS_type_any,
-                                         false,  // bSecurityEnabled - unused
-                                         NULL,   // reserved
-                                         &bss_list) != ERROR_SUCCESS) {
-    return -1;
-  }
-  // According to http://www.attnetclient.com/kb/questions.php?questionid=75
-  // WlanGetNetworkBssList can sometimes return success, but leave the bss
-  // list as NULL.
-  if (!bss_list)
-    return -1;
-
-  const base::TimeDelta duration = base::TimeTicks::Now() - start_time;
-
-  UMA_HISTOGRAM_CUSTOM_TIMES(
-      "Net.Wifi.ScanLatency",
-      duration,
-      base::TimeDelta::FromMilliseconds(1),
-      base::TimeDelta::FromMinutes(1),
-      100);
-
-
-  int found = 0;
-  for (int i = 0; i < static_cast<int>(bss_list->dwNumberOfItems); ++i) {
-    AccessPointData access_point_data;
-    if (GetNetworkData(bss_list->wlanBssEntries[i], &access_point_data)) {
-      ++found;
-      data->insert(access_point_data);
-    }
-  }
-
-  (*WlanFreeMemory_function_)(bss_list);
-
-  return found;
-}
-
-// WindowsNdisApi
-WindowsNdisApi::WindowsNdisApi(
-    std::vector<base::string16>* interface_service_names)
-    : oid_buffer_size_(kInitialBufferSize) {
-  DCHECK(!interface_service_names->empty());
-  interface_service_names_.swap(*interface_service_names);
-}
-
-WindowsNdisApi::~WindowsNdisApi() {
-}
-
-WindowsNdisApi* WindowsNdisApi::Create() {
-  std::vector<base::string16> interface_service_names;
-  if (GetInterfacesNDIS(&interface_service_names)) {
-    return new WindowsNdisApi(&interface_service_names);
-  }
-  return NULL;
-}
-
-bool WindowsNdisApi::GetAccessPointData(WifiData::AccessPointDataSet* data) {
-  DCHECK(data);
-  int interfaces_failed = 0;
-  int interfaces_succeeded = 0;
-
-  for (int i = 0; i < static_cast<int>(interface_service_names_.size()); ++i) {
-    // First, check that we have a DOS device for this adapter.
-    if (!DefineDosDeviceIfNotExists(interface_service_names_[i])) {
-      continue;
-    }
-
-    // Get the handle to the device. This will fail if the named device is not
-    // valid.
-    HANDLE adapter_handle = GetFileHandle(interface_service_names_[i]);
-    if (adapter_handle == INVALID_HANDLE_VALUE) {
-      continue;
-    }
-
-    // Get the data.
-    if (GetInterfaceDataNDIS(adapter_handle, data)) {
-      ++interfaces_succeeded;
-    } else {
-      ++interfaces_failed;
-    }
-
-    // Clean up.
-    CloseHandle(adapter_handle);
-    UndefineDosDevice(interface_service_names_[i]);
-  }
-
-  // Return true if at least one interface succeeded, or at the very least none
-  // failed.
-  return interfaces_succeeded > 0 || interfaces_failed == 0;
-}
-
-bool WindowsNdisApi::GetInterfacesNDIS(
-    std::vector<base::string16>* interface_service_names_out) {
-  HKEY network_cards_key = NULL;
-  if (RegOpenKeyEx(
-      HKEY_LOCAL_MACHINE,
-      L"Software\\Microsoft\\Windows NT\\CurrentVersion\\NetworkCards",
-      0,
-      KEY_READ,
-      &network_cards_key) != ERROR_SUCCESS) {
-    return false;
-  }
-  DCHECK(network_cards_key);
-
-  for (int i = 0; ; ++i) {
-    TCHAR name[kStringLength];
-    DWORD name_size = kStringLength;
-    FILETIME time;
-    if (RegEnumKeyEx(network_cards_key,
-                     i,
-                     name,
-                     &name_size,
-                     NULL,
-                     NULL,
-                     NULL,
-                     &time) != ERROR_SUCCESS) {
-      break;
-    }
-    HKEY hardware_key = NULL;
-    if (RegOpenKeyEx(network_cards_key, name, 0, KEY_READ, &hardware_key) !=
-        ERROR_SUCCESS) {
-      break;
-    }
-    DCHECK(hardware_key);
-
-    TCHAR service_name[kStringLength];
-    DWORD service_name_size = kStringLength;
-    DWORD type = 0;
-    if (RegQueryValueEx(hardware_key,
-                        L"ServiceName",
-                        NULL,
-                        &type,
-                        reinterpret_cast<LPBYTE>(service_name),
-                        &service_name_size) == ERROR_SUCCESS) {
-      interface_service_names_out->push_back(service_name);
-    }
-    RegCloseKey(hardware_key);
-  }
-
-  RegCloseKey(network_cards_key);
-  return true;
-}
-
-
-bool WindowsNdisApi::GetInterfaceDataNDIS(HANDLE adapter_handle,
-                                          WifiData::AccessPointDataSet* data) {
-  DCHECK(data);
-
-  std::unique_ptr<BYTE, base::FreeDeleter> buffer(
-      static_cast<BYTE*>(malloc(oid_buffer_size_)));
-  if (buffer == NULL) {
-    return false;
-  }
-
-  DWORD bytes_out;
-  int result;
-
-  while (true) {
-    bytes_out = 0;
-    result = PerformQuery(adapter_handle, buffer.get(),
-                          oid_buffer_size_, &bytes_out);
-    if (result == ERROR_GEN_FAILURE ||  // Returned by some Intel cards.
-        result == ERROR_INSUFFICIENT_BUFFER ||
-        result == ERROR_MORE_DATA ||
-        result == NDIS_STATUS_INVALID_LENGTH ||
-        result == NDIS_STATUS_BUFFER_TOO_SHORT) {
-      // The buffer we supplied is too small, so increase it. bytes_out should
-      // provide the required buffer size, but this is not always the case.
-      if (bytes_out > static_cast<DWORD>(oid_buffer_size_)) {
-        oid_buffer_size_ = bytes_out;
-      } else {
-        oid_buffer_size_ *= 2;
-      }
-      if (!ResizeBuffer(oid_buffer_size_, &buffer)) {
-        oid_buffer_size_ = kInitialBufferSize;  // Reset for next time.
-        return false;
-      }
-    } else {
-      // The buffer is not too small.
-      break;
-    }
-  }
-  DCHECK(buffer.get());
-
-  if (result == ERROR_SUCCESS) {
-    NDIS_802_11_BSSID_LIST* bssid_list =
-        reinterpret_cast<NDIS_802_11_BSSID_LIST*>(buffer.get());
-    GetDataFromBssIdList(*bssid_list, oid_buffer_size_, data);
-  }
-
-  return true;
-}
-
-bool GetNetworkData(const WLAN_BSS_ENTRY& bss_entry,
-                    AccessPointData* access_point_data) {
-  // Currently we get only MAC address, signal strength and SSID.
-  DCHECK(access_point_data);
-  access_point_data->mac_address = MacAddressAsString16(bss_entry.dot11Bssid);
-  access_point_data->radio_signal_strength = bss_entry.lRssi;
-  // bss_entry.dot11Ssid.ucSSID is not null-terminated.
-  base::UTF8ToUTF16(reinterpret_cast<const char*>(bss_entry.dot11Ssid.ucSSID),
-                    static_cast<ULONG>(bss_entry.dot11Ssid.uSSIDLength),
-                    &access_point_data->ssid);
-  // TODO(steveblock): Is it possible to get the following?
-  // access_point_data->signal_to_noise
-  // access_point_data->age
-  // access_point_data->channel
-  return true;
-}
-
-bool UndefineDosDevice(const base::string16& device_name) {
-  // We remove only the mapping we use, that is \Device\<device_name>.
-  base::string16 target_path = L"\\Device\\" + device_name;
-  return DefineDosDevice(
-      DDD_RAW_TARGET_PATH | DDD_REMOVE_DEFINITION | DDD_EXACT_MATCH_ON_REMOVE,
-      device_name.c_str(),
-      target_path.c_str()) == TRUE;
-}
-
-bool DefineDosDeviceIfNotExists(const base::string16& device_name) {
-  // We create a DOS device name for the device at \Device\<device_name>.
-  base::string16 target_path = L"\\Device\\" + device_name;
-
-  TCHAR target[kStringLength];
-  if (QueryDosDevice(device_name.c_str(), target, kStringLength) > 0 &&
-      target_path.compare(target) == 0) {
-    // Device already exists.
-    return true;
-  }
-
-  if (GetLastError() != ERROR_FILE_NOT_FOUND) {
-    return false;
-  }
-
-  if (!DefineDosDevice(DDD_RAW_TARGET_PATH,
-                       device_name.c_str(),
-                       target_path.c_str())) {
-    return false;
-  }
-
-  // Check that the device is really there.
-  return QueryDosDevice(device_name.c_str(), target, kStringLength) > 0 &&
-      target_path.compare(target) == 0;
-}
-
-HANDLE GetFileHandle(const base::string16& device_name) {
-  // We access a device with DOS path \Device\<device_name> at
-  // \\.\<device_name>.
-  base::string16 formatted_device_name = L"\\\\.\\" + device_name;
-
-  return CreateFile(formatted_device_name.c_str(),
-                    GENERIC_READ,
-                    FILE_SHARE_READ | FILE_SHARE_WRITE,  // share mode
-                    0,  // security attributes
-                    OPEN_EXISTING,
-                    0,  // flags and attributes
-                    INVALID_HANDLE_VALUE);
-}
-
-int PerformQuery(HANDLE adapter_handle,
-                 BYTE* buffer,
-                 DWORD buffer_size,
-                 DWORD* bytes_out) {
-  DWORD oid = OID_802_11_BSSID_LIST;
-  if (!DeviceIoControl(adapter_handle,
-                       IOCTL_NDIS_QUERY_GLOBAL_STATS,
-                       &oid,
-                       sizeof(oid),
-                       buffer,
-                       buffer_size,
-                       bytes_out,
-                       NULL)) {
-    return GetLastError();
-  }
-  return ERROR_SUCCESS;
-}
-
-bool ResizeBuffer(int requested_size,
-                  std::unique_ptr<BYTE, base::FreeDeleter>* buffer) {
-  DCHECK_GT(requested_size, 0);
-  DCHECK(buffer);
-  if (requested_size > kMaximumBufferSize) {
-    buffer->reset();
-    return false;
-  }
-
-  buffer->reset(reinterpret_cast<BYTE*>(
-      realloc(buffer->release(), requested_size)));
-  return buffer != NULL;
-}
-
-bool GetSystemDirectory(base::string16* path) {
-  DCHECK(path);
-  // Return value includes terminating NULL.
-  int buffer_size = ::GetSystemDirectory(NULL, 0);
-  if (buffer_size == 0) {
-    return false;
-  }
-  std::unique_ptr<base::char16[]> buffer(new base::char16[buffer_size]);
-
-  // Return value excludes terminating NULL.
-  int characters_written = ::GetSystemDirectory(buffer.get(), buffer_size);
-  if (characters_written == 0) {
-    return false;
-  }
-  DCHECK_EQ(buffer_size - 1, characters_written);
-
-  path->assign(buffer.get(), characters_written);
-
-  if (*path->rbegin() != L'\\') {
-    path->append(L"\\");
-  }
-  DCHECK_EQ(L'\\', *path->rbegin());
-  return true;
-}
-}  // namespace
-
-}  // namespace content