Created AttestationPolicyObserver.
    
AttestationPolicyObserver performs Chrome OS attestation work in
response to policy changes.
    
This CL integrates AttestationPolicyObserver with the Chrome OS
device policy infrastructure.  It also defines a AttestationCAClient
skeleton which is necessary to instantiate AttestationFlow and changes
AttestationFlow to take ownership of its ServerProxy instance.
    
BUG=chromium:219959
TEST=unit_tests; chromeos_unittests

Review URL: https://chromiumcodereview.appspot.com/12556004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195266 0039d316-1c4b-4281-b951-d872f2087c98
20 files changed