On enterprise machines read policy from the registry.

This will allow the usage of third party policy management
software in enteprise deployments of Chrome on Windows.

BUG=259236

Review URL: https://codereview.chromium.org/152633003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253358 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed