[GCPW] Disable GCPW signin dialog if Chrome is not running under winlogon

desktop.

Bug: 960774
Change-Id: I5fbacb88d28d9a2c3414409c82c832ad8e4b647d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625306
Commit-Queue: Tien Mai <tienmai@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Joe Mason <joenotcharles@google.com>
Reviewed-by: Greg Thompson <grt@chromium.org>
Reviewed-by: Tommy Martino <tmartino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664722}

base/win/win_util.cc

@@ -761,6 +761,38 @@ void* GetUser32FunctionPointer(const char* function_name,
   return nullptr;
 }
 
+string16 GetWindowObjectName(HANDLE handle) {
+  // Get the size of the name.
+  string16 object_name;
+
+  DWORD size = 0;
+  ::GetUserObjectInformation(handle, UOI_NAME, nullptr, 0, &size);
+  if (!size) {
+    DPCHECK(false);
+    return object_name;
+  }
+
+  LOG_ASSERT(size % sizeof(wchar_t) == 0u);
+
+  // Query the name of the object.
+  if (!::GetUserObjectInformation(
+          handle, UOI_NAME, WriteInto(&object_name, size / sizeof(wchar_t)),
+          size, &size)) {
+    DPCHECK(false);
+  }
+
+  return object_name;
+}
+
+bool IsRunningUnderDesktopName(StringPiece16 desktop_name) {
+  HDESK thread_desktop = ::GetThreadDesktop(::GetCurrentThreadId());
+  if (!thread_desktop)
+    return false;
+
+  string16 current_desktop_name = GetWindowObjectName(thread_desktop);
+  return EqualsCaseInsensitiveASCII(current_desktop_name, desktop_name);
+}
+
 ScopedDomainStateForTesting::ScopedDomainStateForTesting(bool state)
     : initial_state_(IsEnrolledToDomain()) {
   *GetDomainEnrollmentStateStorage() = state;

base/win/win_util.h

@@ -31,6 +31,7 @@
 #include "base/base_export.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
 
 struct IPropertyStore;
 struct _tagpropertykey;
@@ -92,7 +93,8 @@ BASE_EXPORT bool SetAppIdForPropertyStore(IPropertyStore* property_store,
 
 // Adds the specified |command| using the specified |name| to the AutoRun key.
 // |root_key| could be HKCU or HKLM or the root of any user hive.
-BASE_EXPORT bool AddCommandToAutoRun(HKEY root_key, const string16& name,
+BASE_EXPORT bool AddCommandToAutoRun(HKEY root_key,
+                                     const string16& name,
                                      const string16& command);
 // Removes the command specified by |name| from the AutoRun key. |root_key|
 // could be HKCU or HKLM or the root of any user hive.
@@ -213,6 +215,14 @@ BASE_EXPORT void* GetUser32FunctionPointer(
     const char* function_name,
     NativeLibraryLoadError* error = nullptr);
 
+// Returns the name of a desktop or a window station.
+BASE_EXPORT string16 GetWindowObjectName(HANDLE handle);
+
+// Checks if the calling thread is running under a desktop with the name
+// given by |desktop_name|. |desktop_name| is ASCII case insensitive (non-ASCII
+// characters will be compared with exact matches).
+BASE_EXPORT bool IsRunningUnderDesktopName(StringPiece16 desktop_name);
+
 // Allows changing the domain enrolled state for the life time of the object.
 // The original state is restored upon destruction.
 class BASE_EXPORT ScopedDomainStateForTesting {

base/win/win_util_unittest.cc

@@ -100,5 +100,31 @@ TEST(BaseWinUtilTest, String16FromGUID) {
   EXPECT_STREQ(as_wcstr(guid_string16), clsid_string.get());
 }
 
+TEST(BaseWinUtilTest, GetWindowObjectName) {
+  base::string16 created_desktop_name(STRING16_LITERAL("test_desktop"));
+  HDESK desktop_handle =
+      ::CreateDesktop(created_desktop_name.c_str(), nullptr, nullptr, 0,
+                      DESKTOP_CREATEWINDOW | DESKTOP_READOBJECTS |
+                          READ_CONTROL | WRITE_DAC | WRITE_OWNER,
+                      nullptr);
+
+  ASSERT_NE(desktop_handle, nullptr);
+  EXPECT_EQ(created_desktop_name, GetWindowObjectName(desktop_handle));
+  ASSERT_TRUE(::CloseDesktop(desktop_handle));
+}
+
+TEST(BaseWinUtilTest, IsRunningUnderDesktopName) {
+  HDESK thread_desktop = ::GetThreadDesktop(::GetCurrentThreadId());
+
+  ASSERT_NE(thread_desktop, nullptr);
+  base::string16 desktop_name = GetWindowObjectName(thread_desktop);
+
+  EXPECT_TRUE(IsRunningUnderDesktopName(desktop_name));
+  EXPECT_TRUE(IsRunningUnderDesktopName(base::ToLowerASCII(desktop_name)));
+  EXPECT_TRUE(IsRunningUnderDesktopName(base::ToUpperASCII(desktop_name)));
+  EXPECT_FALSE(IsRunningUnderDesktopName(
+      desktop_name + STRING16_LITERAL("_non_existent_desktop_name")));
+}
+
 }  // namespace win
 }  // namespace base

chrome/browser/ui/BUILD.gn

@@ -2298,6 +2298,7 @@ jumbo_split_static_library("ui") {
     ]
     deps += [
       "//chrome/browser/safe_browsing/chrome_cleaner:public",
+      "//chrome/browser/ui/startup:buildflags",
       "//chrome/browser/win/conflicts:module_info",
       "//chrome/credential_provider/common:common_constants",
       "//components/search_engines",

chrome/browser/ui/startup/BUILD.gn

+# Copyright 2019 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.
+
+import("//build/buildflag_header.gni")
+import("//build/config/chrome_build.gni")
+
+# Allow browser tests that startup with --gcpw-signin flag only on
+# non-Google Chrome builds.
+can_test_gcpw_signin_startup = !is_chrome_branded
+
+buildflag_header("buildflags") {
+  header = "buildflags.h"
+  flags = [ "CAN_TEST_GCPW_SIGNIN_STARTUP=$can_test_gcpw_signin_startup" ]
+}

chrome/browser/ui/startup/credential_provider_signin_dialog_win.cc

@@ -13,6 +13,7 @@
 #include "base/json/json_writer.h"
 #include "base/strings/string16.h"
 #include "base/syslog_logging.h"
+#include "base/win/win_util.h"
 #include "chrome/browser/signin/signin_promo.h"
 #include "chrome/browser/ui/browser_dialogs.h"
 #include "chrome/browser/ui/startup/credential_provider_signin_info_fetcher_win.h"
@@ -32,6 +33,10 @@
 
 namespace {
 
+#if BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+bool g_enable_gcpw_signin_during_tests = false;
+#endif  // BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+
 // This message must match the one sent in inline_login.js: sendLSTFetchResults.
 constexpr char kLSTFetchResultsMessage[] = "lstFetchResults";
 
@@ -391,22 +396,49 @@ bool ValidateSigninCompleteResult(const std::string& access_token,
          signin_result.is_dict();
 }
 
-void StartGCPWSignin(const base::CommandLine& command_line,
+#if BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+void EnableGcpwSigninDialogForTesting(bool enable) {
+  g_enable_gcpw_signin_during_tests = enable;
+}
+#endif  // BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+
+bool CanStartGCPWSignin() {
+#if BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+  if (g_enable_gcpw_signin_during_tests)
+    return true;
+#endif  // BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+  // Ensure that we are running under a "winlogon" desktop before starting the
+  // gcpw sign in dialog.
+  return base::win::IsRunningUnderDesktopName(STRING16_LITERAL("winlogon"));
+}
+
+bool StartGCPWSignin(const base::CommandLine& command_line,
                      content::BrowserContext* context) {
-  // This keep_alive is created since there is no browser created when
-  // --gcpw-logon is specified. Since there is no browser there is no holder of
-  // a ScopedKeepAlive present that will ensure Chrome kills itself when the
-  // last keep alive is released. So instead, keep the keep alive across the
-  // callbacks that will be sent during the signin process. Once the full fetch
-  // of the information necesssary for the GCPW is finished (or there is a
-  // failure) release the keep alive so that Chrome can shutdown.
+  // If we are prevented from showing gcpw signin, return false and write our
+  // result so that the launch fails and the process can exit gracefully.
+  if (!CanStartGCPWSignin()) {
+    base::Value failure_result(base::Value::Type::DICTIONARY);
+    failure_result.SetKey(credential_provider::kKeyExitCode,
+                          base::Value(static_cast<int>(
+                              credential_provider::kUiecMissingSigninData)));
+    WriteResultToHandle(failure_result);
+    return false;
+  }
 
+  // This keep_alive is created since there is no browser created when
+  // --gcpw-logon is specified. Since there is no browser there is no holder
+  // of a ScopedKeepAlive present that will ensure Chrome kills itself when
+  // the last keep alive is released. So instead, keep the keep alive across
+  // the callbacks that will be sent during the signin process. Once the full
+  // fetch of the information necesssary for the GCPW is finished (or there is
+  // a failure) release the keep alive so that Chrome can shutdown.
   ShowCredentialProviderSigninDialog(
       command_line, context,
       base::BindOnce(&HandleSigninCompleteForGcpwLogin,
                      std::make_unique<ScopedKeepAlive>(
                          KeepAliveOrigin::CREDENTIAL_PROVIDER_SIGNIN_DIALOG,
                          KeepAliveRestartOption::DISABLED)));
+  return true;
 }
 
 views::WebDialogView* ShowCredentialProviderSigninDialog(

chrome/browser/ui/startup/credential_provider_signin_dialog_win.h

@@ -9,6 +9,7 @@
 
 #include "base/callback.h"
 #include "base/memory/scoped_refptr.h"
+#include "chrome/browser/ui/startup/buildflags.h"
 
 namespace base {
 class CommandLine;
@@ -42,7 +43,9 @@ using HandleGcpwSigninCompleteResult =
 // to choose an  account to logon to Windows. Once the signin is complete, the
 // flow will automatically start requesting additional information required by
 // GCPW to complete Windows logon.
-void StartGCPWSignin(const base::CommandLine& command_line,
+// Returns false if the dialog could not be loaded due to the current execution
+// mode.
+bool StartGCPWSignin(const base::CommandLine& command_line,
                      content::BrowserContext* context);
 
 // This function displays a dialog window with a Gaia signin page. Once
@@ -54,4 +57,10 @@ views::WebDialogView* ShowCredentialProviderSigninDialog(
     content::BrowserContext* context,
     HandleGcpwSigninCompleteResult signin_complete_handler);
 
+#if BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+// Allow displaying of GCPW signin dialog when not under the winlogon desktop
+// for testing purposes.
+void EnableGcpwSigninDialogForTesting(bool enable);
+#endif  // BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+
 #endif  // CHROME_BROWSER_UI_STARTUP_CREDENTIAL_PROVIDER_SIGNIN_DIALOG_WIN_H_

chrome/browser/ui/startup/credential_provider_signin_dialog_win_browsertest.cc

@@ -8,6 +8,7 @@
 #include "base/test/test_switches.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/startup/buildflags.h"
 #include "chrome/browser/ui/startup/credential_provider_signin_dialog_win.h"
 #include "chrome/browser/ui/startup/credential_provider_signin_dialog_win_test_data.h"
 #include "chrome/browser/ui/test/test_browser_dialog.h"
@@ -375,31 +376,86 @@ INSTANTIATE_TEST_SUITE_P(
 // the integration of the dialog into Chrome, This test mainly verifies
 // correct start up state if we provide the --gcpw-signin switch.
 
-class CredentialProviderSigninDialogWinIntegrationTest
+class CredentialProviderSigninDialogWinIntegrationTestBase
     : public CredentialProviderSigninDialogWinBaseTest {
  protected:
-  CredentialProviderSigninDialogWinIntegrationTest();
-
+  CredentialProviderSigninDialogWinIntegrationTestBase();
   // InProcessBrowserTest:
   void SetUpCommandLine(base::CommandLine* command_line) override;
 
-  // CredentialProviderSigninDialogWinBaseTest:
-  void WaitForDialogToLoad() override;
-
  private:
-  DISALLOW_COPY_AND_ASSIGN(CredentialProviderSigninDialogWinIntegrationTest);
+  DISALLOW_COPY_AND_ASSIGN(
+      CredentialProviderSigninDialogWinIntegrationTestBase);
 };
 
-CredentialProviderSigninDialogWinIntegrationTest::
-    CredentialProviderSigninDialogWinIntegrationTest()
+CredentialProviderSigninDialogWinIntegrationTestBase::
+    CredentialProviderSigninDialogWinIntegrationTestBase()
     : CredentialProviderSigninDialogWinBaseTest() {}
 
-void CredentialProviderSigninDialogWinIntegrationTest::SetUpCommandLine(
+void CredentialProviderSigninDialogWinIntegrationTestBase::SetUpCommandLine(
     base::CommandLine* command_line) {
   command_line->AppendSwitch(::credential_provider::kGcpwSigninSwitch);
 }
 
-void CredentialProviderSigninDialogWinIntegrationTest::WaitForDialogToLoad() {
+// In the default state, the dialog would not be allowed to be displayed since
+// Chrome will not be running on Winlogon desktop.
+class CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest
+    : public CredentialProviderSigninDialogWinIntegrationTestBase {
+ protected:
+  CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(
+      CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest);
+};
+
+CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest::
+    CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest()
+    : CredentialProviderSigninDialogWinIntegrationTestBase() {}
+
+IN_PROC_BROWSER_TEST_F(
+    CredentialProviderSigninDialogWinIntegrationDesktopVerificationTest,
+    DialogFailsToLoadOnIncorrectDesktop) {
+  // Normally the GCPW signin dialog should only run on "winlogon" desktops. If
+  // we are just running the test, we should not be under this desktop and the
+  // dialog should fail to load.
+
+  // No widgets should have been created.
+  views::Widget::Widgets all_widgets = views::test::WidgetTest::GetAllWidgets();
+  EXPECT_EQ(all_widgets.size(), 0ull);
+}
+
+#if BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)
+
+// This test overrides the check for the correct desktop to allow the dialog to
+// be displayed even when not running on Winlogon desktop.
+class CredentialProviderSigninDialogWinIntegrationDialogDisplayTest
+    : public CredentialProviderSigninDialogWinIntegrationTestBase {
+ protected:
+  CredentialProviderSigninDialogWinIntegrationDialogDisplayTest();
+  ~CredentialProviderSigninDialogWinIntegrationDialogDisplayTest() override;
+
+  // CredentialProviderSigninDialogWinBaseTest:
+  void WaitForDialogToLoad() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(
+      CredentialProviderSigninDialogWinIntegrationDialogDisplayTest);
+};
+
+CredentialProviderSigninDialogWinIntegrationDialogDisplayTest::
+    CredentialProviderSigninDialogWinIntegrationDialogDisplayTest()
+    : CredentialProviderSigninDialogWinIntegrationTestBase() {
+  EnableGcpwSigninDialogForTesting(true);
+}
+
+CredentialProviderSigninDialogWinIntegrationDialogDisplayTest::
+    ~CredentialProviderSigninDialogWinIntegrationDialogDisplayTest() {
+  EnableGcpwSigninDialogForTesting(false);
+}
+
+void CredentialProviderSigninDialogWinIntegrationDialogDisplayTest::
+    WaitForDialogToLoad() {
   // The browser has already been created by the time this start starts and
   // web_contents_ is not yet available. In this run case there should only
   // be one widget available and that widget should contain the web contents
@@ -412,7 +468,7 @@ void CredentialProviderSigninDialogWinIntegrationTest::WaitForDialogToLoad() {
   web_contents_ = web_dialog->web_contents();
   EXPECT_TRUE(web_contents_);
 
-  CredentialProviderSigninDialogWinBaseTest::WaitForDialogToLoad();
+  CredentialProviderSigninDialogWinIntegrationTestBase::WaitForDialogToLoad();
 
   // When running with --gcpw-signin, browser creation is completely bypassed
   // only a dialog for the signin should be created directly. In a normal
@@ -421,7 +477,8 @@ void CredentialProviderSigninDialogWinIntegrationTest::WaitForDialogToLoad() {
   EXPECT_FALSE(browser());
 }
 
-IN_PROC_BROWSER_TEST_F(CredentialProviderSigninDialogWinIntegrationTest,
+IN_PROC_BROWSER_TEST_F(
+    CredentialProviderSigninDialogWinIntegrationDialogDisplayTest,
     ShowDialogOnlyTest) {
   WaitForDialogToLoad();
   EXPECT_TRUE(
@@ -431,7 +488,8 @@ IN_PROC_BROWSER_TEST_F(CredentialProviderSigninDialogWinIntegrationTest,
   RunUntilBrowserProcessQuits();
 }
 
-IN_PROC_BROWSER_TEST_F(CredentialProviderSigninDialogWinIntegrationTest,
+IN_PROC_BROWSER_TEST_F(
+    CredentialProviderSigninDialogWinIntegrationDialogDisplayTest,
     EscapeClosesDialogTest) {
   WaitForDialogToLoad();
   views::Widget::Widgets all_widgets = views::test::WidgetTest::GetAllWidgets();
@@ -441,3 +499,5 @@ IN_PROC_BROWSER_TEST_F(CredentialProviderSigninDialogWinIntegrationTest,
   (*all_widgets.begin())->OnKeyEvent(&escape_key_event);
   RunUntilBrowserProcessQuits();
 }
+
+#endif  // BUILDFLAG(CAN_TEST_GCPW_SIGNIN_STARTUP)

chrome/browser/ui/startup/startup_browser_creator_impl.cc

@@ -358,9 +358,14 @@ bool StartupBrowserCreatorImpl::Launch(Profile* profile,
   // signin page.
   if (command_line_.HasSwitch(credential_provider::kGcpwSigninSwitch)) {
     DCHECK(profile_->IsIncognitoProfile());
-    // NOTE: All launch urls are ignored when running with --gcpw-logon since
+    // NOTE: All launch urls are ignored when running with --gcpw-signin since
     // this mode only loads Google's sign in page.
-    StartGCPWSignin(command_line_, profile_);
+
+    // If GCPW signin dialog fails, returning false here will allow Chrome to
+    // exit gracefully during the launch.
+    if (!StartGCPWSignin(command_line_, profile_))
+      return false;
+
     RecordLaunchModeHistogram(LM_CREDENTIAL_PROVIDER_SIGNIN);
     return true;
   }

content/browser/gpu/gpu_process_host.cc

@@ -414,13 +414,7 @@ class GpuSandboxedProcessLauncherDelegate
     if (UseOpenGLRenderer())
       return true;
 
-    HDESK thread_desktop = ::GetThreadDesktop(::GetCurrentThreadId());
-    if (!thread_desktop)
-      return false;
-
-    base::string16 desktop_name = sandbox::GetWindowObjectName(thread_desktop);
-    ::CloseDesktop(thread_desktop);
-    return !lstrcmpi(desktop_name.c_str(), L"winlogon");
+    return base::win::IsRunningUnderDesktopName(STRING16_LITERAL("winlogon"));
   }
 
   base::CommandLine cmd_line_;

sandbox/win/src/sandbox_policy_base.cc

@@ -13,6 +13,7 @@
 #include "base/macros.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
+#include "base/win/win_util.h"
 #include "base/win/windows_version.h"
 #include "sandbox/win/src/filesystem_policy.h"
 #include "sandbox/win/src/interception.h"
@@ -215,7 +216,7 @@ ResultCode PolicyBase::CreateAlternateDesktop(bool alternate_winstation) {
 
     // Verify that everything is fine.
     if (!alternate_winstation_handle_ ||
-        GetWindowObjectName(alternate_winstation_handle_).empty())
+        base::win::GetWindowObjectName(alternate_winstation_handle_).empty())
       return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
 
     // Create the destkop.
@@ -226,7 +227,7 @@ ResultCode PolicyBase::CreateAlternateDesktop(bool alternate_winstation) {
 
     // Verify that everything is fine.
     if (!alternate_desktop_handle_ ||
-        GetWindowObjectName(alternate_desktop_handle_).empty()) {
+        base::win::GetWindowObjectName(alternate_desktop_handle_).empty()) {
       return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
     }
   } else {
@@ -242,7 +243,8 @@ ResultCode PolicyBase::CreateAlternateDesktop(bool alternate_winstation) {
 
     // Verify that everything is fine.
     if (!alternate_desktop_local_winstation_handle_ ||
-        GetWindowObjectName(alternate_desktop_local_winstation_handle_)
+        base::win::GetWindowObjectName(
+            alternate_desktop_local_winstation_handle_)
             .empty()) {
       return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
     }

sandbox/win/src/window.cc

@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "base/logging.h"
+#include "base/win/win_util.h"
 #include "sandbox/win/src/acl.h"
 #include "sandbox/win/src/sid.h"
 
@@ -127,29 +128,6 @@ ResultCode CreateAltDesktop(HWINSTA winsta, HDESK* desktop) {
   return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
 }
 
-base::string16 GetWindowObjectName(HANDLE handle) {
-  // Get the size of the name.
-  DWORD size = 0;
-  ::GetUserObjectInformation(handle, UOI_NAME, nullptr, 0, &size);
-
-  if (!size) {
-    NOTREACHED();
-    return base::string16();
-  }
-
-  // Create the buffer that will hold the name.
-  std::unique_ptr<wchar_t[]> name_buffer(new wchar_t[size]);
-
-  // Query the name of the object.
-  if (!::GetUserObjectInformation(handle, UOI_NAME, name_buffer.get(), size,
-                                  &size)) {
-    NOTREACHED();
-    return base::string16();
-  }
-
-  return base::string16(name_buffer.get());
-}
-
 base::string16 GetFullDesktopName(HWINSTA winsta, HDESK desktop) {
   if (!desktop) {
     NOTREACHED();
@@ -158,11 +136,11 @@ base::string16 GetFullDesktopName(HWINSTA winsta, HDESK desktop) {
 
   base::string16 name;
   if (winsta) {
-    name = GetWindowObjectName(winsta);
+    name = base::win::GetWindowObjectName(winsta);
     name += L'\\';
   }
 
-  name += GetWindowObjectName(desktop);
+  name += base::win::GetWindowObjectName(desktop);
   return name;
 }
 

sandbox/win/src/window.h

@@ -27,9 +27,6 @@ ResultCode CreateAltWindowStation(HWINSTA* winsta);
 // the function will return SBOX_ERROR_FAILED_TO_SWITCH_BACK_WINSTATION.
 ResultCode CreateAltDesktop(HWINSTA winsta, HDESK* desktop);
 
-// Returns the name of a desktop or a window station.
-base::string16 GetWindowObjectName(HANDLE handle);
-
 // Returns the name of the desktop referenced by |desktop|. If a window
 // station is specified, the name is prepended with the window station name,
 // followed by a backslash. This name can be used as the lpDesktop parameter