Add immutable settings checks when handling policy.

When receiving device policy from the server, make sure that the device
is an enterprise device and the policy information is meant for the user
who registered the device. While at it, move all the enterprise-related
install attributes checking to a helper.

BUG=chromium-os:14197
TEST=unit tests

Review URL: http://codereview.chromium.org/6869042

git-svn-id: http://src.chromium.org/svn/trunk/src/chrome/browser/policy/proto@81932 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
1 file changed