(Also remove from enrollment status in crosh.)

Mattias, do you have any objections?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0c08e95b4d061021f5ecee2a38465aa238c93d2f

commit 0c08e95b4d061021f5ecee2a38465aa238c93d2f
Author: tnagel <tnagel@chromium.org>
Date: Thu Aug 18 12:03:55 2016

Make EnterpriseInstallAttributes::GetRegistrationUser() private.

In the long run, it should probably be removed.

BUG= 638713 

Review-Url: https://codereview.chromium.org/2252173002
Cr-Commit-Position: refs/heads/master@{#412797}

[modify] https://crrev.com/0c08e95b4d061021f5ecee2a38465aa238c93d2f/chrome/browser/chromeos/policy/enterprise_install_attributes.cc
[modify] https://crrev.com/0c08e95b4d061021f5ecee2a38465aa238c93d2f/chrome/browser/chromeos/policy/enterprise_install_attributes.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/42d7ea0a129585044fa4461e7d581ad88e4525dc

commit 42d7ea0a129585044fa4461e7d581ad88e4525dc
Author: tnagel <tnagel@chromium.org>
Date: Thu Oct 13 10:14:17 2016

Remove unused email from install attributes and add support for AD.

Notable changes:
* Simplify attribute accessors by ensuring that attribute members
  are always self-consistent.
* Drop distinction between unset and empty attributes.
* Strict enforcement of *all* attributes being identical on
  re-locking.
* IsEnterpriseDevice() evaluates the device mode instead of
  the (deprecated) user.
* Improve encapsulation of StubInstallAttributes by disabling
  direct member access, provide high-level setters instead.

BUG= 639295 ,  638713 
TBR=achuith (chrome/browser/chromeos/{app_mode,login,system})
TBR=reillyg (chrome/browser/extensions)
TBR=eroman (chrome/browser/net)
TBR=bauerb (chrome/browser/ui/webui)

Review-Url: https://codereview.chromium.org/2403053003
Cr-Commit-Position: refs/heads/master@{#424994}

[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/login/wizard_controller_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/affiliated_invalidation_service_provider_impl_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/blocking_login_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/device_cloud_policy_initializer_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/device_status_collector_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/policy/enrollment_handler_chromeos.h
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/settings/install_attributes.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/settings/install_attributes.h
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/settings/install_attributes_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/settings/stub_install_attributes.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/settings/stub_install_attributes.h
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/chromeos/system/device_disabling_manager_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/extensions/api/enterprise_device_attributes/enterprise_device_attributes_apitest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/extensions/api/enterprise_platform_keys_private/enterprise_platform_keys_private_api_unittest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/extensions/api/identity/identity_apitest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/net/errorpage_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/chrome/browser/ui/webui/options/preferences_browsertest.cc
[modify] https://crrev.com/42d7ea0a129585044fa4461e7d581ad88e4525dc/components/policy/core/common/cloud/cloud_policy_constants.h