Move encryptor API out of webdata.

This justs moves encryptor out of components/webdata/encryptor one layer
up to components/encryptor.

BUG=341293
TEST=None
R=thestig@chromium.org,joi@chromium.org,bcwhite@chromium.org
TBR=rvargas

Review URL: https://codereview.chromium.org/168993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252563 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252563