diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 44185dca385708..4ee0034ab21769 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5992,12 +5992,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
         <message name="IDS_FLAGS_DISABLE_SAML_SIGNIN_DESCRIPTION" desc="Description for the flag to disables SAML sign-in support.">
           Disables SAML sign-in support for Chrome OS sign-in.
         </message>
-        <message name="IDS_FLAGS_ENABLE_MULTI_PROFILES_NAME" desc="Name for the flag to enable multi-profile support.">
-          Enable multiprofiles mode.
-        </message>
-        <message name="IDS_FLAGS_ENABLE_MULTI_PROFILES_DESCRIPTION" desc="Description for the flag to enable multi-profile support.">
-          This is an experimental mode to run several profiles/users simultaneously during a browsing session. Features may break or change significantly.
-        </message>
       </if>
       <message name="IDS_FLAGS_DISABLE_ACCELERATED_VIDEO_DECODE_NAME" desc="Name of the flag to disable accelerated video decode where available.">
         Disable hardware-accelerated video decode.
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 66303f5cad183f..e367947ec1f0c9 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1029,13 +1029,6 @@ const Experiment kExperiments[] = {
     kOsCrOS,
     SINGLE_VALUE_TYPE(chromeos::switches::kDisableSamlSignin),
   },
-  {
-    "enable-multi-profiles",
-    IDS_FLAGS_ENABLE_MULTI_PROFILES_NAME,
-    IDS_FLAGS_ENABLE_MULTI_PROFILES_DESCRIPTION,
-    kOsCrOS,
-    SINGLE_VALUE_TYPE(switches::kMultiProfiles),
-  },
   {
     "disable-display-color-calibration",
     IDS_FLAGS_DISABLE_DISPLAY_COLOR_CALIBRATION_NAME,
diff --git a/chrome/browser/chrome_browser_field_trials_desktop.cc b/chrome/browser/chrome_browser_field_trials_desktop.cc
index 29871dec70d7b2..eeae4d27d9c9b3 100644
--- a/chrome/browser/chrome_browser_field_trials_desktop.cc
+++ b/chrome/browser/chrome_browser_field_trials_desktop.cc
@@ -28,10 +28,6 @@
 #include "net/spdy/spdy_session.h"
 #include "ui/base/layout.h"
 
-#if defined(OS_CHROMEOS)
-#include "chrome/browser/chromeos/login/user_manager.h"
-#endif
-
 namespace chrome {
 
 namespace {
@@ -115,16 +111,6 @@ void SetupPreReadFieldTrial() {
   trial->group();
 }
 
-#if defined(OS_CHROMEOS)
-void SetupChromeOSMultiProfilesAllowedTrial() {
-  const char kTrialName[] = "ChromeOSMultiProfilesAllowed";
-  if (chromeos::UserManager::IsMultipleProfilesAllowed())
-    base::FieldTrialList::CreateFieldTrial(kTrialName, "allowed")->group();
-  else
-    base::FieldTrialList::CreateFieldTrial(kTrialName, "not_allowed")->group();
-}
-#endif  // defined(OS_CHROMEOS)
-
 }  // namespace
 
 void SetupDesktopFieldTrials(const CommandLine& parsed_command_line,
@@ -137,9 +123,6 @@ void SetupDesktopFieldTrials(const CommandLine& parsed_command_line,
   DisableShowProfileSwitcherTrialIfNecessary();
   SetupShowAppLauncherPromoFieldTrial(local_state);
   SetupPreReadFieldTrial();
-#if defined(OS_CHROMEOS)
-  SetupChromeOSMultiProfilesAllowedTrial();
-#endif
 }
 
 }  // namespace chrome
diff --git a/chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc b/chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc
index ce1e3aff16ab4e..61657b5c1cda03 100644
--- a/chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc
@@ -394,12 +394,6 @@ bool FileBrowserPrivateVisitDesktopFunction::RunSync() {
   const std::vector<linked_ptr<api::file_browser_private::ProfileInfo> >&
       profiles = GetLoggedInProfileInfoList(GetAssociatedWebContents());
 
-  // Check the multi-profile support.
-  if (!profiles::IsMultipleProfilesEnabled()) {
-    SetError("Multi-profile support is not enabled.");
-    return false;
-  }
-
   chrome::MultiUserWindowManager* const window_manager =
       chrome::MultiUserWindowManager::GetInstance();
   DCHECK(window_manager);
diff --git a/chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc b/chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc
index e72e76f4f336b2..097a8079955357 100644
--- a/chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc
+++ b/chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc
@@ -6,18 +6,22 @@
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
+#include "base/path_service.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/drive/drive_integration_service.h"
 #include "chrome/browser/chromeos/drive/test_util.h"
 #include "chrome/browser/chromeos/file_manager/drive_test_util.h"
 #include "chrome/browser/chromeos/file_manager/volume_manager.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/drive/fake_drive_service.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_constants.h"
+#include "chrome/common/chrome_paths.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/test/test_utils.h"
@@ -65,6 +69,11 @@ const char kRestrictedMountPointName[] = "restricted";
 // Default file content for the test files.
 const char kTestFileContent[] = "This is some test content.";
 
+// User account email and directory hash for secondary account for multi-profile
+// sensitive test cases.
+const char kSecondProfileAccount[] = "profile2@test.com";
+const char kSecondProfileHash[] = "fileBrowserApiTestProfile2";
+
 // Sets up the initial file system state for native local and restricted native
 // local file systems. The hierarchy is the same as for the drive file system.
 // The directory is created at unique_temp_dir/|mount_point_name| path.
@@ -501,11 +510,16 @@ class MultiProfileDriveFileSystemExtensionApiTest :
   MultiProfileDriveFileSystemExtensionApiTest() : second_profile(NULL) {}
 
   virtual void SetUpOnMainThread() OVERRIDE {
+    base::FilePath user_data_directory;
+    PathService::Get(chrome::DIR_USER_DATA, &user_data_directory);
+    chromeos::UserManager::Get()->UserLoggedIn(kSecondProfileAccount,
+                                               kSecondProfileHash,
+                                               false);
     // Set up the secondary profile.
-    base::FilePath profile_dir;
-    base::CreateNewTempDirectory(base::FilePath::StringType(), &profile_dir);
-    profile_dir = profile_dir.AppendASCII(
-        std::string(chrome::kProfileDirPrefix) + "fileBrowserApiTestProfile2");
+    base::FilePath profile_dir =
+        user_data_directory.Append(
+            chromeos::ProfileHelper::GetUserProfileDir(
+                kSecondProfileHash).BaseName());
     second_profile =
         g_browser_process->profile_manager()->GetProfile(profile_dir);
 
diff --git a/chrome/browser/chromeos/file_manager/path_util.cc b/chrome/browser/chromeos/file_manager/path_util.cc
index 27e02fc2c2dd0b..59256ba4d7a6a1 100644
--- a/chrome/browser/chromeos/file_manager/path_util.cc
+++ b/chrome/browser/chromeos/file_manager/path_util.cc
@@ -33,16 +33,13 @@ const base::FilePath::CharType kBuggyDriveFolderPath[] =
 }  // namespace
 
 base::FilePath GetDownloadsFolderForProfile(Profile* profile) {
-  if (!base::SysInfo::IsRunningOnChromeOS() &&
-      !chromeos::UserManager::IsMultipleProfilesAllowed()) {
-    // On the developer run on Linux desktop build, if multiple profiles are
-    // not enabled, use $HOME/Downloads for ease for accessing local files for
-    // debugging.
+  if (!base::SysInfo::IsRunningOnChromeOS()) {
+    // On the developer run on Linux desktop build, use $HOME/Downloads for ease
+    // for accessing local files for debugging.
     base::FilePath path;
     CHECK(PathService::Get(base::DIR_HOME, &path));
     return path.AppendASCII(kDownloadsFolderName);
   }
-
   return profile->GetPath().AppendASCII(kDownloadsFolderName);
 }
 
diff --git a/chrome/browser/chromeos/file_manager/volume_manager.cc b/chrome/browser/chromeos/file_manager/volume_manager.cc
index 1d3ea1e5287cb3..9edaa4f7c53512 100644
--- a/chrome/browser/chromeos/file_manager/volume_manager.cc
+++ b/chrome/browser/chromeos/file_manager/volume_manager.cc
@@ -15,6 +15,7 @@
 #include "base/prefs/pref_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/sys_info.h"
 #include "chrome/browser/chromeos/drive/drive_integration_service.h"
 #include "chrome/browser/chromeos/drive/file_errors.h"
 #include "chrome/browser/chromeos/drive/file_system_interface.h"
@@ -289,15 +290,21 @@ void VolumeManager::Initialize() {
                                       new_path);
   }
 
-  // Register 'Downloads' folder for the profile to the file system.
-  const base::FilePath downloads =
-      file_manager::util::GetDownloadsFolderForProfile(profile_);
-  const bool success = RegisterDownloadsMountPoint(profile_, downloads);
-  DCHECK(success);
-
-  DoMountEvent(chromeos::MOUNT_ERROR_NONE,
-               CreateDownloadsVolumeInfo(downloads),
-               kNotRemounting);
+  static bool added_downloads = false;
+  if (base::SysInfo::IsRunningOnChromeOS() || !added_downloads) {
+    // Register 'Downloads' folder for the profile to the file system.
+    // On non-ChromeOS system (test+development), we should do this only for
+    // the first registered profile.
+    const base::FilePath downloads =
+        file_manager::util::GetDownloadsFolderForProfile(profile_);
+    const bool success = RegisterDownloadsMountPoint(profile_, downloads);
+    added_downloads = success;
+    DCHECK(success);
+
+    DoMountEvent(chromeos::MOUNT_ERROR_NONE,
+                 CreateDownloadsVolumeInfo(downloads),
+                 kNotRemounting);
+  }
 
   // Subscribe to DriveIntegrationService.
   if (drive_integration_service_) {
diff --git a/chrome/browser/chromeos/login/chrome_restart_request.cc b/chrome/browser/chromeos/login/chrome_restart_request.cc
index a477c17c0f2b18..daf7a44fdfdfda 100644
--- a/chrome/browser/chromeos/login/chrome_restart_request.cc
+++ b/chrome/browser/chromeos/login/chrome_restart_request.cc
@@ -129,7 +129,6 @@ std::string DeriveCommandLine(const GURL& start_url,
     ::switches::kGpuSandboxAllowSysVShm,
     ::switches::kGpuSandboxFailuresFatal,
     ::switches::kGpuSandboxStartAfterInitialization,
-    ::switches::kMultiProfiles,
     ::switches::kNoSandbox,
     ::switches::kNumRasterThreads,
     ::switches::kPpapiFlashArgs,
diff --git a/chrome/browser/chromeos/login/kiosk_browsertest.cc b/chrome/browser/chromeos/login/kiosk_browsertest.cc
index 44869e08ab9302..aeec99901e7c57 100644
--- a/chrome/browser/chromeos/login/kiosk_browsertest.cc
+++ b/chrome/browser/chromeos/login/kiosk_browsertest.cc
@@ -34,6 +34,7 @@
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_test_message_listener.h"
 #include "chrome/browser/profiles/profile_impl.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/ui/webui/chromeos/login/kiosk_app_menu_handler.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
@@ -431,19 +432,12 @@ class KioskTest : public OobeBaseTest {
   // run. Note this must be called before app profile is loaded.
   void SetupAppProfile(const std::string& relative_app_profile_dir) {
     base::FilePath app_profile_dir;
-    if (CommandLine::ForCurrentProcess()->HasSwitch(
-            ::switches::kMultiProfiles)) {
-      KioskAppManager::App app_data;
-      CHECK(KioskAppManager::Get()->GetApp(test_app_id(), &app_data));
-      std::string app_user_id_hash =
-          CryptohomeClient::GetStubSanitizedUsername(app_data.user_id);
-      app_profile_dir =
-          ProfileHelper::GetProfilePathByUserIdHash(app_user_id_hash);
-    } else {
-      ASSERT_TRUE(PathService::Get(chrome::DIR_USER_DATA, &app_profile_dir));
-      app_profile_dir = app_profile_dir.Append(
-          ProfileHelper::GetProfileDirByLegacyLoginProfileSwitch());
-    }
+    KioskAppManager::App app_data;
+    CHECK(KioskAppManager::Get()->GetApp(test_app_id(), &app_data));
+    std::string app_user_id_hash =
+        CryptohomeClient::GetStubSanitizedUsername(app_data.user_id);
+    app_profile_dir =
+        ProfileHelper::GetProfilePathByUserIdHash(app_user_id_hash);
     ASSERT_TRUE(base::CreateDirectory(app_profile_dir));
 
     base::FilePath test_data_dir;
diff --git a/chrome/browser/chromeos/login/login_browsertest.cc b/chrome/browser/chromeos/login/login_browsertest.cc
index 9b996324b28c83..68cf98a80da41d 100644
--- a/chrome/browser/chromeos/login/login_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_browsertest.cc
@@ -10,6 +10,7 @@
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/login/wizard_controller.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
@@ -34,7 +35,8 @@ class LoginUserTest : public InProcessBrowserTest {
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     command_line->AppendSwitchASCII(
         chromeos::switches::kLoginUser, "TestUser@gmail.com");
-    command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile, "user");
+    command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile,
+                                    "hash");
   }
 };
 
@@ -43,7 +45,8 @@ class LoginGuestTest : public InProcessBrowserTest {
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     command_line->AppendSwitch(chromeos::switches::kGuestSession);
     command_line->AppendSwitch(::switches::kIncognito);
-    command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile, "user");
+    command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile,
+                                    "hash");
     command_line->AppendSwitchASCII(chromeos::switches::kLoginUser,
                                     chromeos::UserManager::kGuestUserName);
   }
@@ -64,7 +67,8 @@ class LoginSigninTest : public InProcessBrowserTest {
   }
 
   virtual void SetUpOnMainThread() OVERRIDE {
-    ASSERT_TRUE(tracing::BeginTracingWithWatch("ui", "ui", "ShowLoginWebUI", 1));
+    ASSERT_TRUE(tracing::BeginTracingWithWatch(
+        "ui", "ui", "ShowLoginWebUI", 1));
   }
 };
 
@@ -73,7 +77,9 @@ class LoginSigninTest : public InProcessBrowserTest {
 // This profile should NOT be an OTR profile.
 IN_PROC_BROWSER_TEST_F(LoginUserTest, UserPassed) {
   Profile* profile = browser()->profile();
-  EXPECT_EQ("user", profile->GetPath().BaseName().value());
+  std::string profile_base_path("hash");
+  profile_base_path.insert(0, chrome::kProfileDirPrefix);
+  EXPECT_EQ(profile_base_path, profile->GetPath().BaseName().value());
   EXPECT_FALSE(profile->IsOffTheRecord());
 }
 
diff --git a/chrome/browser/chromeos/login/login_manager_test.cc b/chrome/browser/chromeos/login/login_manager_test.cc
index 4d8738d6bf01e3..2f103a44018703 100644
--- a/chrome/browser/chromeos/login/login_manager_test.cc
+++ b/chrome/browser/chromeos/login/login_manager_test.cc
@@ -66,14 +66,14 @@ void LoginManagerTest::SetExpectedCredentials(const std::string& username,
 
 bool LoginManagerTest::TryToLogin(const std::string& username,
                                   const std::string& password) {
-  if (!AddUserTosession(username, password))
+  if (!AddUserToSession(username, password))
     return false;
   if (const User* active_user = UserManager::Get()->GetActiveUser())
     return active_user->email() == username;
   return false;
 }
 
-bool LoginManagerTest::AddUserTosession(const std::string& username,
+bool LoginManagerTest::AddUserToSession(const std::string& username,
                                         const std::string& password) {
   ExistingUserController* controller =
       ExistingUserController::current_controller();
@@ -101,7 +101,7 @@ void LoginManagerTest::LoginUser(const std::string& username) {
 
 void LoginManagerTest::AddUser(const std::string& username) {
   SetExpectedCredentials(username, "password");
-  EXPECT_TRUE(AddUserTosession(username, "password"));
+  EXPECT_TRUE(AddUserToSession(username, "password"));
 }
 
 void LoginManagerTest::JSExpect(const std::string& expression) {
diff --git a/chrome/browser/chromeos/login/login_manager_test.h b/chrome/browser/chromeos/login/login_manager_test.h
index b05db4860117f5..50d23c118ec8db 100644
--- a/chrome/browser/chromeos/login/login_manager_test.h
+++ b/chrome/browser/chromeos/login/login_manager_test.h
@@ -47,7 +47,7 @@ class LoginManagerTest : public InProcessBrowserTest {
   // Tries to add user to session with |username| and |password|. Returns false
   // if attempt has failed. this function does the same as TryToLogin but
   // doesn't check that new user become active user.
-  bool AddUserTosession(const std::string& username,
+  bool AddUserToSession(const std::string& username,
                         const std::string& password);
 
   // Login user with |username|. User should be registered using RegisterUser().
diff --git a/chrome/browser/chromeos/login/login_utils_browsertest.cc b/chrome/browser/chromeos/login/login_utils_browsertest.cc
index 441e39c7e7a3da..3642cff033247e 100644
--- a/chrome/browser/chromeos/login/login_utils_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_utils_browsertest.cc
@@ -34,10 +34,10 @@
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/rlz/rlz.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/chrome_paths.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/chrome_unit_test_suite.h"
 #include "chrome/test/base/scoped_testing_local_state.h"
@@ -207,9 +207,6 @@ class LoginUtilsTest : public testing::Test,
     command_line->AppendSwitchASCII(
         policy::switches::kDeviceManagementUrl, kDMServer);
 
-    if (!command_line->HasSwitch(::switches::kMultiProfiles))
-      command_line->AppendSwitchASCII(switches::kLoginProfile, "user");
-
     // DBusThreadManager should be initialized before io_thread_state_, as
     // DBusThreadManager is used from chromeos::ProxyConfigServiceImpl,
     // which is part of io_thread_state_.
@@ -526,28 +523,11 @@ class LoginUtilsTest : public testing::Test,
   DISALLOW_COPY_AND_ASSIGN(LoginUtilsTest);
 };
 
-class LoginUtilsParamTest
-    : public LoginUtilsTest,
-      public testing::WithParamInterface<bool> {
- public:
-  LoginUtilsParamTest() {}
-
-  virtual void SetUp() OVERRIDE {
-    CommandLine* command_line = CommandLine::ForCurrentProcess();
-    if (GetParam())
-      command_line->AppendSwitch(::switches::kMultiProfiles);
-    LoginUtilsTest::SetUp();
-  }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(LoginUtilsParamTest);
-};
-
 class LoginUtilsBlockingLoginTest
     : public LoginUtilsTest,
       public testing::WithParamInterface<int> {};
 
-TEST_P(LoginUtilsParamTest, NormalLoginDoesntBlock) {
+TEST_F(LoginUtilsTest, NormalLoginDoesntBlock) {
   UserManager* user_manager = UserManager::Get();
   EXPECT_FALSE(user_manager->IsUserLoggedIn());
   EXPECT_FALSE(connector_->IsEnterpriseManaged());
@@ -563,7 +543,7 @@ TEST_P(LoginUtilsParamTest, NormalLoginDoesntBlock) {
   EXPECT_EQ(kUsername, user_manager->GetLoggedInUser()->email());
 }
 
-TEST_P(LoginUtilsParamTest, EnterpriseLoginDoesntBlockForNormalUser) {
+TEST_F(LoginUtilsTest, EnterpriseLoginDoesntBlockForNormalUser) {
   UserManager* user_manager = UserManager::Get();
   EXPECT_FALSE(user_manager->IsUserLoggedIn());
   EXPECT_FALSE(connector_->IsEnterpriseManaged());
@@ -588,7 +568,7 @@ TEST_P(LoginUtilsParamTest, EnterpriseLoginDoesntBlockForNormalUser) {
 }
 
 #if defined(ENABLE_RLZ)
-TEST_P(LoginUtilsParamTest, RlzInitialized) {
+TEST_F(LoginUtilsTest, RlzInitialized) {
   // No RLZ brand code set initially.
   EXPECT_FALSE(local_state_.Get()->HasPrefPath(prefs::kRLZBrand));
 
@@ -723,10 +703,6 @@ INSTANTIATE_TEST_CASE_P(
     LoginUtilsBlockingLoginTest,
     testing::Values(0, 1, 2, 3, 4, 5));
 
-INSTANTIATE_TEST_CASE_P(LoginUtilsParamTestInstantiation,
-                        LoginUtilsParamTest,
-                        testing::Bool());
-
 }  // namespace
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/login/user.h b/chrome/browser/chromeos/login/user.h
index ac6457db4656a3..650daf93cffdbf 100644
--- a/chrome/browser/chromeos/login/user.h
+++ b/chrome/browser/chromeos/login/user.h
@@ -258,7 +258,9 @@ class User : public ash::UserInfo {
     display_name_ = display_name;
   }
 
-  void set_given_name(const base::string16& given_name) { given_name_ = given_name; }
+  void set_given_name(const base::string16& given_name) {
+    given_name_ = given_name;
+  }
 
   void set_display_email(const std::string& display_email) {
     display_email_ = display_email;
diff --git a/chrome/browser/chromeos/login/user_manager.cc b/chrome/browser/chromeos/login/user_manager.cc
index 41685d57062f20..c446255b02f431 100644
--- a/chrome/browser/chromeos/login/user_manager.cc
+++ b/chrome/browser/chromeos/login/user_manager.cc
@@ -58,9 +58,10 @@ PendingUserSessionsRestoreFinished() {
 UserManager::UserSessionStateObserver::~UserSessionStateObserver() {
 }
 
-UserManager::UserAccountData::UserAccountData(const base::string16& display_name,
-                                              const base::string16& given_name,
-                                              const std::string& locale)
+UserManager::UserAccountData::UserAccountData(
+    const base::string16& display_name,
+    const base::string16& given_name,
+    const std::string& locale)
     : display_name_(display_name),
       given_name_(given_name),
       locale_(locale) {
@@ -91,18 +92,15 @@ UserManager* UserManager::Get() {
   return g_user_manager;
 }
 
-// static
-bool UserManager::IsMultipleProfilesAllowed() {
-  return CommandLine::ForCurrentProcess()->HasSwitch(
-      ::switches::kMultiProfiles);
-}
-
 UserManager::~UserManager() {
 }
 
 // static
 UserManager* UserManager::SetForTesting(UserManager* user_manager) {
   UserManager* previous_user_manager = g_user_manager;
+  if (previous_user_manager)
+    previous_user_manager->Shutdown();
+
   g_user_manager = user_manager;
   return previous_user_manager;
 }
diff --git a/chrome/browser/chromeos/login/user_manager.h b/chrome/browser/chromeos/login/user_manager.h
index cb76d41709a6bc..ffba8630989c2d 100644
--- a/chrome/browser/chromeos/login/user_manager.h
+++ b/chrome/browser/chromeos/login/user_manager.h
@@ -122,9 +122,6 @@ class UserManager {
   // Registers user manager preferences.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
-  // Returns true if multiple profiles support is allowed.
-  static bool IsMultipleProfilesAllowed();
-
   virtual ~UserManager();
 
   virtual MultiProfileUserController* GetMultiProfileUserController() = 0;
diff --git a/chrome/browser/chromeos/login/user_manager_impl.cc b/chrome/browser/chromeos/login/user_manager_impl.cc
index f6d486216d9c54..4a56400838ee38 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -52,6 +52,7 @@
 #include "chrome/browser/net/nss_context.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/common/chrome_constants.h"
@@ -288,6 +289,7 @@ void UserManagerImpl::Shutdown() {
   multi_profile_user_controller_.reset();
   avatar_policy_observer_.reset();
   wallpaper_policy_observer_.reset();
+  registrar_.RemoveAll();
 }
 
 MultiProfileUserController* UserManagerImpl::GetMultiProfileUserController() {
@@ -314,9 +316,6 @@ const UserList& UserManagerImpl::GetUsers() const {
 }
 
 UserList UserManagerImpl::GetUsersAdmittedForMultiProfile() const {
-  if (!UserManager::IsMultipleProfilesAllowed())
-    return UserList();
-
   // Supervised users are not allowed to use multi profile.
   if (logged_in_users_.size() == 1 &&
       GetPrimaryUser()->GetType() != User::USER_TYPE_REGULAR)
@@ -415,9 +414,6 @@ void UserManagerImpl::UserLoggedIn(const std::string& user_id,
                                    bool browser_restart) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(::switches::kMultiProfiles))
-    DCHECK(!IsUserLoggedIn());
-
   User* user = FindUserInListAndModify(user_id);
   if (active_user_ && user) {
     user->set_is_logged_in(true);
@@ -493,9 +489,6 @@ void UserManagerImpl::UserLoggedIn(const std::string& user_id,
 }
 
 void UserManagerImpl::SwitchActiveUser(const std::string& user_id) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(::switches::kMultiProfiles))
-    return;
-
   User* user = FindUserAndModify(user_id);
   if (!user) {
     NOTREACHED() << "Switching to a non-existing user";
@@ -684,29 +677,37 @@ User* UserManagerImpl::GetUserByProfile(Profile* profile) const {
   if (ProfileHelper::IsSigninProfile(profile))
     return NULL;
 
-  if (IsMultipleProfilesAllowed()) {
-    const std::string username_hash =
-        ProfileHelper::GetUserIdHashFromProfile(profile);
-    const UserList& users = GetUsers();
-    const UserList::const_iterator pos = std::find_if(
-        users.begin(), users.end(), UserHashMatcher(username_hash));
-    if (pos != users.end())
-      return *pos;
-
-    // Many tests do not have their users registered with UserManager and
-    // runs here. If |active_user_| matches |profile|, returns it.
-    return active_user_ &&
-                   ProfileHelper::GetProfilePathByUserIdHash(
-                       active_user_->username_hash()) == profile->GetPath()
-               ? active_user_
-               : NULL;
+  // Special case for non-CrOS tests that do create several profiles
+  // and don't really care about mapping to the real user.
+  // Without multi-profiles on Chrome OS such tests always got active_user_.
+  // Now these tests will specify special flag to continue working.
+  // In future those tests can get a proper CrOS configuration i.e. register
+  // and login several users if they want to work with an additional profile.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kIgnoreUserProfileMappingForTests)) {
+    return active_user_;
   }
-  return active_user_;
+
+  const std::string username_hash =
+      ProfileHelper::GetUserIdHashFromProfile(profile);
+  const UserList& users = GetUsers();
+  const UserList::const_iterator pos = std::find_if(
+      users.begin(), users.end(), UserHashMatcher(username_hash));
+  if (pos != users.end())
+    return *pos;
+
+  // Many tests do not have their users registered with UserManager and
+  // runs here. If |active_user_| matches |profile|, returns it.
+  return active_user_ &&
+                 ProfileHelper::GetProfilePathByUserIdHash(
+                     active_user_->username_hash()) == profile->GetPath()
+             ? active_user_
+             : NULL;
 }
 
 Profile* UserManagerImpl::GetProfileByUser(const User* user) const {
   Profile* profile = NULL;
-  if (IsMultipleProfilesAllowed() && user->is_profile_created())
+  if (user->is_profile_created())
     profile = ProfileHelper::GetProfileByUserIdHash(user->username_hash());
   else
     profile = ProfileManager::GetActiveUserProfile();
@@ -1867,19 +1868,9 @@ base::FilePath UserManagerImpl::GetUserProfileDir(
   // ProfileManager and use only this function to construct profile path.
   // TODO(nkostylev): Cleanup profile dir related code paths crbug.com/294233
   base::FilePath profile_dir;
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(::switches::kMultiProfiles)) {
-    const User* user = FindUser(user_id);
-    if (user && !user->username_hash().empty())
-      profile_dir = ProfileHelper::GetUserProfileDir(user->username_hash());
-  } else if (command_line.HasSwitch(chromeos::switches::kLoginProfile)) {
-    profile_dir = ProfileHelper::GetProfileDirByLegacyLoginProfileSwitch();
-  } else {
-    // We should never be logged in with no profile dir unless
-    // multi-profiles are enabled.
-    NOTREACHED();
-    profile_dir = base::FilePath();
-  }
+  const User* user = FindUser(user_id);
+  if (user && !user->username_hash().empty())
+    profile_dir = ProfileHelper::GetUserProfileDir(user->username_hash());
 
   ProfileManager* profile_manager = g_browser_process->profile_manager();
   profile_dir = profile_manager->user_data_dir().Append(profile_dir);
diff --git a/chrome/browser/chromeos/login/user_manager_unittest.cc b/chrome/browser/chromeos/login/user_manager_unittest.cc
index 7654601139e1bf..f9d61b755a6150 100644
--- a/chrome/browser/chromeos/login/user_manager_unittest.cc
+++ b/chrome/browser/chromeos/login/user_manager_unittest.cc
@@ -5,6 +5,8 @@
 #include <cstdlib>
 #include <cstring>
 
+#include "base/command_line.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
 #include "base/run_loop.h"
@@ -16,18 +18,46 @@
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 #include "chrome/browser/chromeos/settings/stub_cros_settings_provider.h"
+#include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/test/base/scoped_testing_local_state.h"
 #include "chrome/test/base/testing_browser_process.h"
+#include "chrome/test/base/testing_profile.h"
+#include "chromeos/chromeos_switches.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/fake_dbus_thread_manager.h"
 #include "chromeos/settings/cros_settings_names.h"
 #include "chromeos/settings/cros_settings_provider.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chromeos {
 
+class UnittestProfileManager : public ::ProfileManagerWithoutInit {
+ public:
+  explicit UnittestProfileManager(const base::FilePath& user_data_dir)
+      : ::ProfileManagerWithoutInit(user_data_dir) {}
+
+ protected:
+  virtual Profile* CreateProfileHelper(
+      const base::FilePath& file_path) OVERRIDE {
+    if (!base::PathExists(file_path)) {
+      if (!base::CreateDirectory(file_path))
+        return NULL;
+    }
+    return new TestingProfile(file_path, NULL);
+  }
+};
+
+
 class UserManagerTest : public testing::Test {
  protected:
   virtual void SetUp() OVERRIDE {
+    CommandLine& command_line = *CommandLine::ForCurrentProcess();
+    command_line.AppendSwitch(::switches::kTestType);
+    command_line.AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+
     cros_settings_ = CrosSettings::Get();
 
     // Replace the real DeviceSettingsProvider with a stub.
@@ -45,6 +75,14 @@ class UserManagerTest : public testing::Test {
     local_state_.reset(
         new ScopedTestingLocalState(TestingBrowserProcess::GetGlobal()));
 
+    ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
+    TestingBrowserProcess::GetGlobal()->SetProfileManager(
+        new UnittestProfileManager(temp_dir_.path()));
+
+    chromeos::FakeDBusThreadManager* dbus_manager =
+        new chromeos::FakeDBusThreadManager();
+    chromeos::DBusThreadManager::InitializeForTesting(dbus_manager);
+
     ResetUserManager();
   }
 
@@ -59,8 +97,10 @@ class UserManagerTest : public testing::Test {
 
     // Shut down the DeviceSettingsService.
     DeviceSettingsService::Get()->UnsetSessionManager();
+    TestingBrowserProcess::GetGlobal()->SetProfileManager(NULL);
 
     base::RunLoop().RunUntilIdle();
+    chromeos::DBusThreadManager::Shutdown();
   }
 
   UserManagerImpl* GetUserManagerImpl() const {
@@ -120,6 +160,7 @@ class UserManagerTest : public testing::Test {
   ScopedTestCrosSettings test_cros_settings_;
 
   scoped_ptr<ScopedUserManagerEnabler> user_manager_enabler_;
+  base::ScopedTempDir temp_dir_;
 };
 
 TEST_F(UserManagerTest, RetrieveTrustedDevicePolicies) {
diff --git a/chrome/browser/chromeos/login/wallpaper_manager.cc b/chrome/browser/chromeos/login/wallpaper_manager.cc
index fd8c4b20c69eff..22f6b144bbba7b 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager.cc
+++ b/chrome/browser/chromeos/login/wallpaper_manager.cc
@@ -548,28 +548,24 @@ void WallpaperManager::EnsureLoggedInUserWallpaperLoaded() {
 void WallpaperManager::ClearDisposableWallpaperCache() {
   // Cancel callback for previous cache requests.
   weak_factory_.InvalidateWeakPtrs();
-  if (!UserManager::IsMultipleProfilesAllowed()) {
-    wallpaper_cache_.clear();
-  } else {
-    // Keep the wallpaper of logged in users in cache at multi-profile mode.
-    std::set<std::string> logged_in_users_names;
-    const UserList& logged_users = UserManager::Get()->GetLoggedInUsers();
-    for (UserList::const_iterator it = logged_users.begin();
-         it != logged_users.end();
-         ++it) {
-      logged_in_users_names.insert((*it)->email());
-    }
+  // Keep the wallpaper of logged in users in cache at multi-profile mode.
+  std::set<std::string> logged_in_users_names;
+  const UserList& logged_users = UserManager::Get()->GetLoggedInUsers();
+  for (UserList::const_iterator it = logged_users.begin();
+       it != logged_users.end();
+       ++it) {
+    logged_in_users_names.insert((*it)->email());
+  }
 
-    CustomWallpaperMap logged_in_users_cache;
-    for (CustomWallpaperMap::iterator it = wallpaper_cache_.begin();
-         it != wallpaper_cache_.end(); ++it) {
-      if (logged_in_users_names.find(it->first) !=
-          logged_in_users_names.end()) {
-        logged_in_users_cache.insert(*it);
-      }
+  CustomWallpaperMap logged_in_users_cache;
+  for (CustomWallpaperMap::iterator it = wallpaper_cache_.begin();
+       it != wallpaper_cache_.end(); ++it) {
+    if (logged_in_users_names.find(it->first) !=
+        logged_in_users_names.end()) {
+      logged_in_users_cache.insert(*it);
     }
-    wallpaper_cache_ = logged_in_users_cache;
   }
+  wallpaper_cache_ = logged_in_users_cache;
 }
 
 base::FilePath WallpaperManager::GetCustomWallpaperPath(
@@ -920,8 +916,7 @@ void WallpaperManager::SetCustomWallpaper(const std::string& user_id,
     GetPendingWallpaper(user_id, false)->ResetSetWallpaperImage(image, info);
   }
 
-  if (UserManager::IsMultipleProfilesAllowed())
-    wallpaper_cache_[user_id] = image;
+  wallpaper_cache_[user_id] = image;
 }
 
 void WallpaperManager::SetDefaultWallpaperNow(const std::string& user_id) {
@@ -1101,8 +1096,7 @@ void WallpaperManager::SetWallpaperFromImageSkia(const std::string& user_id,
     return;
   WallpaperInfo info;
   info.layout = layout;
-  if (UserManager::IsMultipleProfilesAllowed())
-    wallpaper_cache_[user_id] = image;
+  wallpaper_cache_[user_id] = image;
 
   if (update_wallpaper) {
     GetPendingWallpaper(last_selected_user_, false /* Not delayed */)
@@ -1495,11 +1489,7 @@ void WallpaperManager::OnWallpaperDecoded(
     return;
   }
 
-  // Only cache the user wallpaper at login screen and for multi profile users.
-  if (!UserManager::Get()->IsUserLoggedIn() ||
-      UserManager::IsMultipleProfilesAllowed()) {
-    wallpaper_cache_[user_id] = user_image.image();
-  }
+  wallpaper_cache_[user_id] = user_image.image();
 
   if (update_wallpaper) {
     ash::Shell::GetInstance()
diff --git a/chrome/browser/chromeos/profiles/profile_helper.cc b/chrome/browser/chromeos/profiles/profile_helper.cc
index cda520eef79767..2fb9304cf640d4 100644
--- a/chrome/browser/chromeos/profiles/profile_helper.cc
+++ b/chrome/browser/chromeos/profiles/profile_helper.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chromeos/chromeos_switches.h"
@@ -58,6 +59,11 @@ Profile* ProfileHelper::GetProfileByUserIdHash(
 // static
 base::FilePath ProfileHelper::GetProfilePathByUserIdHash(
     const std::string& user_id_hash) {
+  // Fails for KioskTest.InstallAndLaunchApp test - crbug.com/238985
+  // Will probably fail for Guest session / restart after a crash -
+  // crbug.com/238998
+  // TODO(nkostylev): Remove this check once these bugs are fixed.
+  DCHECK(!user_id_hash.empty());
   ProfileManager* profile_manager = g_browser_process->profile_manager();
   base::FilePath profile_path = profile_manager->user_data_dir();
 
diff --git a/chrome/browser/chromeos/profiles/profile_list_chromeos.cc b/chrome/browser/chromeos/profiles/profile_list_chromeos.cc
index 5860dda9cb329c..4091b2f72d5b8d 100644
--- a/chrome/browser/chromeos/profiles/profile_list_chromeos.cc
+++ b/chrome/browser/chromeos/profiles/profile_list_chromeos.cc
@@ -52,7 +52,7 @@ void ProfileListChromeOS::RebuildMenu() {
 
     gfx::Image icon = gfx::Image((*it)->GetImage());
     if (!CommandLine::ForCurrentProcess()->HasSwitch(
-        switches::kNewProfileManagement)) {
+        switches::kNewProfileManagement) && !icon.IsEmpty()) {
       // old avatar menu uses resized-small images
       icon = profiles::GetAvatarIconForMenu(icon, true);
     }
diff --git a/chrome/browser/extensions/api/networking_private/networking_private_api_chromeos.cc b/chrome/browser/extensions/api/networking_private/networking_private_api_chromeos.cc
index 685290e6ed11e1..6275beaca3e865 100644
--- a/chrome/browser/extensions/api/networking_private/networking_private_api_chromeos.cc
+++ b/chrome/browser/extensions/api/networking_private/networking_private_api_chromeos.cc
@@ -7,12 +7,11 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
-#include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part_chromeos.h"
 #include "chrome/browser/chromeos/net/network_portal_detector.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
-#include "chrome/common/chrome_switches.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/common/extensions/api/networking_private.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/shill_manager_client.h"
@@ -62,13 +61,8 @@ ShillManagerClient::VerificationProperties ConvertVerificationProperties(
 }
 
 std::string GetUserIdHash(Profile* profile) {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kMultiProfiles)) {
-    return g_browser_process->platform_part()->
-        profile_helper()->GetUserIdHashFromProfile(profile);
-  } else {
-    return g_browser_process->platform_part()->
-        profile_helper()->active_user_id_hash();
-  }
+  return g_browser_process->platform_part()->
+      profile_helper()->GetUserIdHashFromProfile(profile);
 }
 
 }  // namespace
diff --git a/chrome/browser/extensions/api/preferences_private/preferences_private_apitest.cc b/chrome/browser/extensions/api/preferences_private/preferences_private_apitest.cc
index 3848a58bad4d63..b17dc80baaeba4 100644
--- a/chrome/browser/extensions/api/preferences_private/preferences_private_apitest.cc
+++ b/chrome/browser/extensions/api/preferences_private/preferences_private_apitest.cc
@@ -29,6 +29,10 @@
 #include "components/sync_driver/sync_prefs.h"
 #include "content/public/browser/browser_context.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 using extensions::PreferencesPrivateGetSyncCategoriesWithoutPassphraseFunction;
 
 namespace {
@@ -107,6 +111,13 @@ class PreferencesPrivateApiTest : public ExtensionApiTest {
   PreferencesPrivateApiTest() : browser_(NULL), service_(NULL) {}
   virtual ~PreferencesPrivateApiTest() {}
 
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
+  }
+
   virtual void SetUpOnMainThread() OVERRIDE {
     ExtensionApiTest::SetUpOnMainThread();
 
diff --git a/chrome/browser/extensions/api/sessions/sessions_apitest.cc b/chrome/browser/extensions/api/sessions/sessions_apitest.cc
index 6d0a7f12825543..e8980ae0f615c7 100644
--- a/chrome/browser/extensions/api/sessions/sessions_apitest.cc
+++ b/chrome/browser/extensions/api/sessions/sessions_apitest.cc
@@ -25,6 +25,10 @@
 #include "sync/api/fake_sync_change_processor.h"
 #include "sync/api/sync_error_factory_mock.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 namespace utils = extension_function_test_utils;
 
 namespace extensions {
@@ -78,6 +82,7 @@ void BuildTabSpecifics(const std::string& tag, int window_id, int tab_id,
 
 class ExtensionSessionsTest : public InProcessBrowserTest {
  public:
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE;
   virtual void SetUpOnMainThread() OVERRIDE;
  protected:
   void CreateTestProfileSyncService();
@@ -96,6 +101,13 @@ class ExtensionSessionsTest : public InProcessBrowserTest {
   scoped_refptr<extensions::Extension> extension_;
 };
 
+void ExtensionSessionsTest::SetUpCommandLine(CommandLine* command_line) {
+#if defined(OS_CHROMEOS)
+  command_line->AppendSwitch(
+      chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
+}
+
 void ExtensionSessionsTest::SetUpOnMainThread() {
   CreateTestProfileSyncService();
   CreateTestExtension();
diff --git a/chrome/browser/extensions/external_provider_impl_chromeos_unittest.cc b/chrome/browser/extensions/external_provider_impl_chromeos_unittest.cc
index f2b97ca60d67f0..93e85c3ad1be4b 100644
--- a/chrome/browser/extensions/external_provider_impl_chromeos_unittest.cc
+++ b/chrome/browser/extensions/external_provider_impl_chromeos_unittest.cc
@@ -10,6 +10,7 @@
 #include "base/test/scoped_path_override.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/customization_document.h"
+#include "chrome/browser/chromeos/login/fake_user_manager.h"
 #include "chrome/browser/extensions/extension_service_unittest.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
@@ -33,7 +34,11 @@ const char kExternalAppId[] = "kekdneafjmhmndejhmbcadfiiofngffo";
 
 class ExternalProviderImplChromeOSTest : public ExtensionServiceTestBase {
  public:
-  ExternalProviderImplChromeOSTest() {}
+  ExternalProviderImplChromeOSTest()
+      : fake_user_manager_(new chromeos::FakeUserManager()),
+        scoped_user_manager_(fake_user_manager_) {
+  }
+
   virtual ~ExternalProviderImplChromeOSTest() {}
 
   void InitServiceWithExternalProviders() {
@@ -78,6 +83,8 @@ class ExternalProviderImplChromeOSTest : public ExtensionServiceTestBase {
   TestingPrefServiceSimple local_state_;
   scoped_ptr<base::ScopedPathOverride> external_externsions_overrides_;
   chromeos::system::MockStatisticsProvider mock_statistics_provider_;
+  chromeos::FakeUserManager* fake_user_manager_;
+  chromeos::ScopedUserManagerEnabler scoped_user_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalProviderImplChromeOSTest);
 };
diff --git a/chrome/browser/extensions/external_provider_impl_unittest.cc b/chrome/browser/extensions/external_provider_impl_unittest.cc
index 27e8c5559baec8..219ef9460af765 100644
--- a/chrome/browser/extensions/external_provider_impl_unittest.cc
+++ b/chrome/browser/extensions/external_provider_impl_unittest.cc
@@ -28,6 +28,7 @@
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/customization_document.h"
+#include "chrome/browser/chromeos/login/fake_user_manager.h"
 #include "chromeos/system/mock_statistics_provider.h"
 #include "chromeos/system/statistics_provider.h"
 #endif
@@ -51,6 +52,10 @@ class ExternalProviderImplTest : public ExtensionServiceTestBase {
   virtual ~ExternalProviderImplTest() {}
 
   void InitServiceWithExternalProviders() {
+#if defined(OS_CHROMEOS)
+    chromeos::ScopedUserManagerEnabler scoped_user_manager(
+        new chromeos::FakeUserManager);
+#endif
     InitializeExtensionServiceWithUpdater();
 
     ProviderCollection providers;
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 29a65ea48f6011..ae45e0d55c910c 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -102,7 +102,6 @@
 #endif
 
 #if defined(OS_CHROMEOS)
-#include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/net/cert_verify_proc_chromeos.h"
 #endif
 
@@ -546,17 +545,15 @@ void IOThread::InitAsync() {
   globals_->host_resolver = CreateGlobalHostResolver(net_log_);
   UpdateDnsClientEnabled();
 #if defined(OS_CHROMEOS)
-  if (chromeos::UserManager::IsMultipleProfilesAllowed()) {
-    // Creates a CertVerifyProc that doesn't allow any profile-provided certs.
-    globals_->cert_verifier.reset(new net::MultiThreadedCertVerifier(
-        new chromeos::CertVerifyProcChromeOS()));
-  } else  // NOLINT Fallthrough to normal verifier if multiprofiles not allowed.
-#endif
-  {
+  // Creates a CertVerifyProc that doesn't allow any profile-provided certs.
+  globals_->cert_verifier.reset(new net::MultiThreadedCertVerifier(
+      new chromeos::CertVerifyProcChromeOS()));
+#else
     globals_->cert_verifier.reset(new net::MultiThreadedCertVerifier(
         net::CertVerifyProc::CreateDefault()));
-  }
-  globals_->transport_security_state.reset(new net::TransportSecurityState());
+#endif
+
+    globals_->transport_security_state.reset(new net::TransportSecurityState());
 #if !defined(USE_OPENSSL)
   // For now, Certificate Transparency is only implemented for platforms
   // that use NSS.
diff --git a/chrome/browser/lifetime/browser_close_manager_browsertest.cc b/chrome/browser/lifetime/browser_close_manager_browsertest.cc
index 42c96c4ec9234c..ef424b8f40e235 100644
--- a/chrome/browser/lifetime/browser_close_manager_browsertest.cc
+++ b/chrome/browser/lifetime/browser_close_manager_browsertest.cc
@@ -43,6 +43,10 @@
 #include "content/test/net/url_request_slow_download_job.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 namespace {
 
 class AppModalDialogObserver {
@@ -248,6 +252,10 @@ class BrowserCloseManagerBrowserTest
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     if (GetParam())
       command_line->AppendSwitch(switches::kEnableFastUnload);
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
   }
 
   void CreateStalledDownload(Browser* browser) {
diff --git a/chrome/browser/metrics/metrics_log_chromeos.cc b/chrome/browser/metrics/metrics_log_chromeos.cc
index 517447feb25416..45a36ac85867ba 100644
--- a/chrome/browser/metrics/metrics_log_chromeos.cc
+++ b/chrome/browser/metrics/metrics_log_chromeos.cc
@@ -201,8 +201,7 @@ void MetricsLogChromeOS::UpdateMultiProfileUserCount() {
   metrics::SystemProfileProto* system_profile =
       uma_proto_->mutable_system_profile();
 
-  if (chromeos::UserManager::IsInitialized() &&
-      chromeos::UserManager::Get()->IsMultipleProfilesAllowed()) {
+  if (chromeos::UserManager::IsInitialized()) {
     size_t user_count = chromeos::UserManager::Get()->GetLoggedInUsers().size();
 
     // We invalidate the user count if it changed while the log was open.
diff --git a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
index 2dc6001a54aad3..071991180a134b 100644
--- a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
+++ b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
@@ -290,8 +290,10 @@ class PerformanceMonitorUncleanExitBrowserTest
  public:
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     PerformanceMonitorBrowserTest::SetUpCommandLine(command_line);
-    if (GetParam())
-      command_line->AppendSwitch(::switches::kMultiProfiles);
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
   }
 
   virtual bool SetUpUserDataDirectory() OVERRIDE {
diff --git a/chrome/browser/prefs/pref_hash_browsertest.cc b/chrome/browser/prefs/pref_hash_browsertest.cc
index 4cfd45b8a700f7..d818c6aaf30a2c 100644
--- a/chrome/browser/prefs/pref_hash_browsertest.cc
+++ b/chrome/browser/prefs/pref_hash_browsertest.cc
@@ -32,6 +32,10 @@
 #include "content/public/test/test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 namespace {
 
 // An observer that returns back to test code after a new profile is
@@ -106,6 +110,10 @@ class PrefHashBrowserTest : public InProcessBrowserTest,
         switches::kForceFieldTrials,
         std::string(chrome_prefs::internals::kSettingsEnforcementTrialName) +
             "/" + GetParam() + "/");
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
   }
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
@@ -164,8 +172,6 @@ class PrefHashBrowserTest : public InProcessBrowserTest,
 
 IN_PROC_BROWSER_TEST_P(PrefHashBrowserTest,
                        MAYBE_PRE_PRE_InitializeUnloadedProfiles) {
-  if (!profiles::IsMultipleProfilesEnabled())
-    return;
   ProfileManager* profile_manager = g_browser_process->profile_manager();
 
   // Create an additional profile.
@@ -194,9 +200,6 @@ IN_PROC_BROWSER_TEST_P(PrefHashBrowserTest,
 
 IN_PROC_BROWSER_TEST_P(PrefHashBrowserTest,
                        MAYBE_PRE_InitializeUnloadedProfiles) {
-  if (!profiles::IsMultipleProfilesEnabled())
-    return;
-
   // Creating the profile would have initialized its hash store. Also, we don't
   // know whether the newly created or original profile will be launched (does
   // creating a profile cause it to be the most recently used?).
@@ -231,9 +234,6 @@ IN_PROC_BROWSER_TEST_P(PrefHashBrowserTest,
 
 IN_PROC_BROWSER_TEST_P(PrefHashBrowserTest,
                        MAYBE_InitializeUnloadedProfiles) {
-  if (!profiles::IsMultipleProfilesEnabled())
-    return;
-
   const base::DictionaryValue* hashes =
       g_browser_process->local_state()->GetDictionary(
           prefs::kProfilePreferenceHashes);
diff --git a/chrome/browser/profiles/profile_browsertest.cc b/chrome/browser/profiles/profile_browsertest.cc
index 2a06e5eae029a8..0cc502f4ea4b0a 100644
--- a/chrome/browser/profiles/profile_browsertest.cc
+++ b/chrome/browser/profiles/profile_browsertest.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/profiles/profile.h"
 
+#include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/prefs/pref_service.h"
@@ -22,6 +23,10 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 namespace {
 
 class MockProfileDelegate : public Profile::Delegate {
@@ -84,7 +89,15 @@ void SpinThreads() {
 
 }  // namespace
 
-typedef InProcessBrowserTest ProfileBrowserTest;
+class ProfileBrowserTest : public InProcessBrowserTest {
+ protected:
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
+  }
+};
 
 // Test OnProfileCreate is called with is_new_profile set to true when
 // creating a new profile synchronously.
diff --git a/chrome/browser/profiles/profile_io_data.cc b/chrome/browser/profiles/profile_io_data.cc
index 9a4234f032ce89..1f49bbb428821f 100644
--- a/chrome/browser/profiles/profile_io_data.cc
+++ b/chrome/browser/profiles/profile_io_data.cc
@@ -990,15 +990,11 @@ void ProfileIOData::Init(
 #if defined(OS_CHROMEOS)
   username_hash_ = profile_params_->username_hash;
   scoped_refptr<net::CertVerifyProc> verify_proc;
-  if (chromeos::UserManager::IsMultipleProfilesAllowed()) {
-    crypto::ScopedPK11Slot public_slot =
-        crypto::GetPublicSlotForChromeOSUser(username_hash_);
-    // The private slot won't be ready by this point. It shouldn't be necessary
-    // for cert trust purposes anyway.
-    verify_proc = new chromeos::CertVerifyProcChromeOS(public_slot.Pass());
-  } else {
-    verify_proc = net::CertVerifyProc::CreateDefault();
-  }
+  crypto::ScopedPK11Slot public_slot =
+      crypto::GetPublicSlotForChromeOSUser(username_hash_);
+  // The private slot won't be ready by this point. It shouldn't be necessary
+  // for cert trust purposes anyway.
+  verify_proc = new chromeos::CertVerifyProcChromeOS(public_slot.Pass());
   if (cert_verifier_) {
     cert_verifier_->InitializeOnIOThread(verify_proc);
     main_request_context_->set_cert_verifier(cert_verifier_.get());
diff --git a/chrome/browser/profiles/profile_manager.cc b/chrome/browser/profiles/profile_manager.cc
index 9e25b1da6fc2a6..e5985b9f39ff3e 100644
--- a/chrome/browser/profiles/profile_manager.cc
+++ b/chrome/browser/profiles/profile_manager.cc
@@ -83,6 +83,7 @@
 #include "chrome/browser/chromeos/login/user.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/cryptohome_client.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ -326,11 +327,12 @@ Profile* ProfileManager::GetPrimaryUserProfile() {
 Profile* ProfileManager::GetActiveUserProfile() {
   ProfileManager* profile_manager = g_browser_process->profile_manager();
 #if defined(OS_CHROMEOS)
-  if (!chromeos::UserManager::IsMultipleProfilesAllowed() ||
-      !profile_manager->IsLoggedIn() ||
-      !chromeos::UserManager::IsInitialized())
+  if (!profile_manager->IsLoggedIn() ||
+      !chromeos::UserManager::IsInitialized()) {
     return profile_manager->GetActiveUserOrOffTheRecordProfileFromPath(
         profile_manager->user_data_dir());
+  }
+
   chromeos::UserManager* manager = chromeos::UserManager::Get();
   const chromeos::User* user = manager->GetActiveUser();
   // To avoid an endless loop (crbug.com/334098) we have to additionally check
@@ -454,20 +456,13 @@ base::FilePath ProfileManager::GetInitialProfileDir() {
       // by default. http://crbug.com/294628
       profile_dir = chromeos::ProfileHelper::
           GetProfileDirByLegacyLoginProfileSwitch();
-    } else if (!command_line.HasSwitch(switches::kMultiProfiles)) {
-      // We should never be logged in with no profile dir unless
-      // multi-profiles are enabled.
-      // In that case profile dir will be defined by user_id hash.
-      NOTREACHED();
-      return base::FilePath("");
     }
     // In case of multi-profiles ignore --login-profile switch.
     // TODO(nkostylev): Some cases like Guest mode will have empty username_hash
     // so default kLoginProfile dir will be used.
     std::string user_id_hash = g_browser_process->platform_part()->
         profile_helper()->active_user_id_hash();
-    if (command_line.HasSwitch(switches::kMultiProfiles) &&
-        !user_id_hash.empty()) {
+    if (!user_id_hash.empty()) {
       profile_dir = g_browser_process->platform_part()->
           profile_helper()->GetActiveUserProfileDir();
     }
@@ -491,20 +486,12 @@ Profile* ProfileManager::GetLastUsedProfile(
     // CrOS multi-profiles implementation is different so GetLastUsedProfile
     // has custom implementation too.
     base::FilePath profile_dir;
-    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-    if (command_line.HasSwitch(switches::kMultiProfiles)) {
-      // In case of multi-profiles we ignore "last used profile" preference
-      // since it may refer to profile that has been in use in previous session.
-      // That profile dir may not be mounted in this session so instead return
-      // active profile from current session.
-      profile_dir = g_browser_process->platform_part()->
-          profile_helper()->GetActiveUserProfileDir();
-    } else {
-      // For legacy (not multi-profiles) implementation always default to
-      // --login-profile value.
-      profile_dir =
-          chromeos::ProfileHelper::GetProfileDirByLegacyLoginProfileSwitch();
-    }
+    // In case of multi-profiles we ignore "last used profile" preference
+    // since it may refer to profile that has been in use in previous session.
+    // That profile dir may not be mounted in this session so instead return
+    // active profile from current session.
+    profile_dir = g_browser_process->platform_part()->
+        profile_helper()->GetActiveUserProfileDir();
 
     base::FilePath profile_path(user_data_dir);
     Profile* profile = GetProfile(profile_path.Append(profile_dir));
diff --git a/chrome/browser/profiles/profile_manager_browsertest.cc b/chrome/browser/profiles/profile_manager_browsertest.cc
index def46bc0713846..9c95d5a27af033 100644
--- a/chrome/browser/profiles/profile_manager_browsertest.cc
+++ b/chrome/browser/profiles/profile_manager_browsertest.cc
@@ -15,7 +15,6 @@
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/host_desktop.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/test_switches.h"
@@ -94,6 +93,13 @@ class ProfileRemovalObserver : public ProfileInfoCacheObserver {
 // TODO(jeremy): crbug.com/103355 - These tests should be enabled on all
 // platforms.
 class ProfileManagerBrowserTest : public InProcessBrowserTest {
+ protected:
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
+  }
 };
 
 #if defined(OS_MACOSX)
@@ -179,21 +185,17 @@ IN_PROC_BROWSER_TEST_F(ProfileManagerBrowserTest, DISABLED_DeleteAllProfiles) {
 
 #if defined(OS_CHROMEOS)
 
-class ProfileManagerCrOSBrowserTest : public ProfileManagerBrowserTest,
-                                      public testing::WithParamInterface<bool> {
+class ProfileManagerCrOSBrowserTest : public ProfileManagerBrowserTest {
  protected:
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
-    if (GetParam()) {
-      command_line->AppendSwitch(::switches::kMultiProfiles);
-      // Use a user hash other than the default chrome::kTestUserProfileDir
-      // so that the prefix case is tested.
-      command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile,
-                                      "test-user-hash");
-    }
+    // Use a user hash other than the default chrome::kTestUserProfileDir
+    // so that the prefix case is tested.
+    command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile,
+                                    "test-user-hash");
   }
 };
 
-IN_PROC_BROWSER_TEST_P(ProfileManagerCrOSBrowserTest, GetLastUsedProfile) {
+IN_PROC_BROWSER_TEST_F(ProfileManagerCrOSBrowserTest, GetLastUsedProfile) {
   // Make sure that last used profile is correct.
   Profile* last_used_profile = ProfileManager::GetLastUsedProfile();
   EXPECT_TRUE(last_used_profile != NULL);
@@ -201,20 +203,11 @@ IN_PROC_BROWSER_TEST_P(ProfileManagerCrOSBrowserTest, GetLastUsedProfile) {
   base::FilePath profile_path;
   PathService::Get(chrome::DIR_USER_DATA, &profile_path);
 
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(switches::kMultiProfiles)) {
-    profile_path = profile_path.AppendASCII(
-        std::string(chrome::kProfileDirPrefix) + "test-user-hash");
-  } else {
-    profile_path = profile_path.AppendASCII(chrome::kTestUserProfileDir);
-  }
+  profile_path = profile_path.AppendASCII(
+      std::string(chrome::kProfileDirPrefix) + "test-user-hash");
   EXPECT_EQ(profile_path.value(), last_used_profile->GetPath().value());
 }
 
-INSTANTIATE_TEST_CASE_P(ProfileManagerCrOSBrowserTestInstantiation,
-                        ProfileManagerCrOSBrowserTest,
-                        testing::Bool());
-
 #endif  // OS_CHROMEOS
 
 // Times out (http://crbug.com/159002)
diff --git a/chrome/browser/profiles/profile_manager_unittest.cc b/chrome/browser/profiles/profile_manager_unittest.cc
index 82e8fd9eb80abb..07c6e9fa651487 100644
--- a/chrome/browser/profiles/profile_manager_unittest.cc
+++ b/chrome/browser/profiles/profile_manager_unittest.cc
@@ -36,6 +36,7 @@
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "grit/generated_resources.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -392,7 +393,7 @@ class ProfileManagerGuestTest : public ProfileManagerTest,
       cl->AppendSwitch(switches::kMultiProfiles);
 
     cl->AppendSwitch(switches::kTestType);
-    if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kMultiProfiles)) {
+    if (profiles::IsMultipleProfilesEnabled()) {
       cl->AppendSwitchASCII(chromeos::switches::kLoginProfile,
                             std::string(chrome::kProfileDirPrefix) +
                                 chromeos::UserManager::kGuestUserName);
diff --git a/chrome/browser/profiles/profiles_state.cc b/chrome/browser/profiles/profiles_state.cc
index 282ffd3f3544b2..dbb330cd65c795 100644
--- a/chrome/browser/profiles/profiles_state.cc
+++ b/chrome/browser/profiles/profiles_state.cc
@@ -20,20 +20,12 @@
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
-#if defined(OS_CHROMEOS)
-#include "chrome/browser/chromeos/login/user_manager.h"
-#endif
-
 namespace profiles {
 
 bool IsMultipleProfilesEnabled() {
 #if defined(OS_ANDROID)
   return false;
 #endif
-#if defined(OS_CHROMEOS)
-  return chromeos::UserManager::IsMultipleProfilesAllowed();
-#endif
-
   return true;
 }
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc b/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
index 5ba5da999320ef..8caf1c59006841 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
@@ -9,6 +9,7 @@
 #include <algorithm>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ref_counted.h"
@@ -35,6 +36,7 @@
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_paths.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
@@ -44,6 +46,10 @@
 #include "sql/statement.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 using content::BrowserThread;
 using content::InterstitialPage;
 using content::WebContents;
@@ -394,6 +400,17 @@ class SafeBrowsingServiceTest : public InProcessBrowserTest {
     SafeBrowsingService::RegisterFactory(NULL);
   }
 
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
+    // Makes sure the auto update is not triggered during the test.
+    // This test will fill up the database using testing prefixes
+    // and urls.
+    command_line->AppendSwitch(switches::kSbDisableAutoUpdate);
+#if defined(OS_CHROMEOS)
+    command_line->AppendSwitch(
+        chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
+  }
+
   virtual void SetUpInProcessBrowserTestFixture() {
     ASSERT_TRUE(test_server()->Start());
   }
diff --git a/chrome/browser/sync/test/integration/sync_test.cc b/chrome/browser/sync/test/integration/sync_test.cc
index e3355f50dbb0f3..9f79709747d0b0 100644
--- a/chrome/browser/sync/test/integration/sync_test.cc
+++ b/chrome/browser/sync/test/integration/sync_test.cc
@@ -75,6 +75,10 @@
 #include "sync/test/fake_server/fake_server_network_resources.h"
 #include "url/gurl.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 using content::BrowserThread;
 using invalidation::InvalidationServiceFactory;
 
@@ -242,6 +246,10 @@ void SyncTest::TearDown() {
 void SyncTest::SetUpCommandLine(base::CommandLine* cl) {
   AddTestSwitches(cl);
   AddOptionalTypesToCommandLine(cl);
+
+#if defined(OS_CHROMEOS)
+  cl->AppendSwitch(chromeos::switches::kIgnoreUserProfileMappingForTests);
+#endif
 }
 
 void SyncTest::AddTestSwitches(base::CommandLine* cl) {
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index bbcaa5d9317fa4..4f6ffe321e8c8e 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -10,10 +10,10 @@
 #include "ash/magnifier/magnifier_constants.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_util.h"
-#include "base/command_line.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/ui/app_list/app_list_service.h"
 #include "chrome/browser/ui/app_list/app_list_view_delegate.h"
 #include "chrome/browser/ui/ash/app_list/app_list_controller_ash.h"
@@ -21,7 +21,6 @@
 #include "chrome/browser/ui/ash/launcher/chrome_launcher_controller.h"
 #include "chrome/browser/ui/ash/launcher/launcher_context_menu.h"
 #include "chrome/browser/ui/browser_commands.h"
-#include "chrome/common/chrome_switches.h"
 #include "components/signin/core/common/profile_management_switches.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
@@ -48,10 +47,7 @@ ChromeShellDelegate::~ChromeShellDelegate() {
 }
 
 bool ChromeShellDelegate::IsMultiProfilesEnabled() const {
-  // TODO(skuhne): There is a function named profiles::IsMultiProfilesEnabled
-  // which does similar things - but it is not the same. We should investigate
-  // if these two could be folded together.
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kMultiProfiles))
+  if (!profiles::IsMultipleProfilesEnabled())
     return false;
 #if defined(OS_CHROMEOS)
   // If there is a user manager, we need to see that we can at least have 2
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 982f3f248177a0..74265799fa0f3a 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1716,6 +1716,8 @@
             '../apps/load_and_launch_browsertest.cc',
             'browser/printing/cloud_print/test/cloud_print_policy_browsertest.cc',
             'browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc',
+            # chromeos does not support profile list avatar menu
+            'browser/profiles/profile_list_desktop_browsertest.cc',
             'browser/service_process/service_process_control_browsertest.cc',
             'browser/signin/signin_browsertest.cc',
             # chromeos does not use cross-platform panels
diff --git a/chrome/common/logging_chrome.cc b/chrome/common/logging_chrome.cc
index 93114258135c54..7398a897e747a9 100644
--- a/chrome/common/logging_chrome.cc
+++ b/chrome/common/logging_chrome.cc
@@ -224,10 +224,9 @@ base::FilePath GetSessionLogFile(const CommandLine& command_line) {
 }
 
 void RedirectChromeLogging(const CommandLine& command_line) {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kMultiProfiles) &&
-      chrome_logging_redirected_) {
+  if (chrome_logging_redirected_) {
     // TODO(nkostylev): Support multiple active users. http://crbug.com/230345
-    LOG(ERROR) << "NOT redirecting logging for multi-profiles case.";
+    LOG(WARNING) << "NOT redirecting logging for multi-profiles case.";
     return;
   }
 
diff --git a/chromeos/chromeos_switches.cc b/chromeos/chromeos_switches.cc
index 77cf81ba93670c..91c825f4d5c9ad 100644
--- a/chromeos/chromeos_switches.cc
+++ b/chromeos/chromeos_switches.cc
@@ -142,6 +142,13 @@ const char kHasChromeOSKeyboard[]           = "has-chromeos-keyboard";
 // If true, the Chromebook has a keyboard with a diamond key.
 const char kHasChromeOSDiamondKey[]         = "has-chromeos-diamond-key";
 
+// If true, profile selection in UserManager will always return active user's
+// profile.
+// TODO(nkostlyev): http://crbug.com/364604 - Get rid of this switch after we
+// turn on multi-profile feature on ChromeOS.
+const char kIgnoreUserProfileMappingForTests[] =
+    "ignore-user-profile-mapping-for-tests";
+
 // Path for the screensaver used in Kiosk mode
 const char kKioskModeScreensaverPath[]      = "kiosk-mode-screensaver-path";
 
diff --git a/chromeos/chromeos_switches.h b/chromeos/chromeos_switches.h
index 0290c2bb452a7b..a2a12680236152 100644
--- a/chromeos/chromeos_switches.h
+++ b/chromeos/chromeos_switches.h
@@ -57,6 +57,7 @@ CHROMEOS_EXPORT extern const char kForceLoginManagerInTests[];
 CHROMEOS_EXPORT extern const char kGuestSession[];
 CHROMEOS_EXPORT extern const char kHasChromeOSDiamondKey[];
 CHROMEOS_EXPORT extern const char kHasChromeOSKeyboard[];
+CHROMEOS_EXPORT extern const char kIgnoreUserProfileMappingForTests[];
 CHROMEOS_EXPORT extern const char kKioskModeScreensaverPath[];
 CHROMEOS_EXPORT extern const char kLoginManager[];
 CHROMEOS_EXPORT extern const char kLoginPassword[];