Moved the --device-management-url switch to the policy component.

BUG=275292
TBR=nkostylev@chromium.org

Review URL: https://codereview.chromium.org/131023004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246115 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246115
Moved the ProxyPolicyProvider to the policy component.

This policy provider gets its policies from a delegate policy provider. It is
used on ChromeOS to allow user cloud policy to override some prefs in Local
State (the providers that override Local State must be ready before the Profile
and user policy are ready).

After moving to the component it will be possible to enable this provider on
iOS builds, so that user cloud policy can override some Local State prefs on
that platform too (such as metrics reporting).

BUG=275292
TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/137203005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246116 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246116