In order for the browser to correctly reason about suborigins, this adds
support to url::Origin to parse and understand suborigins. It separates
requests for hosts and schemes from the embedded suborigin
serialization, while keeping the same-origin policy checks intact so a
suborigin is a different origin from other suborigins at the same
physical origin.

This updates url/origin.* so that given a suborigin encoded in a GURL,
will correctly deserialize the suborigin and store it accordingly, while
the scheme/host/port tuple is left with the real scheme/host/port.
Additionally, removes the content/public/common/origin_util.h functions
for using suborigins since url::Origin should now be used in their
stead.

BUG=336894,649893

Review-Url: https://codereview.chromium.org/2403713002
Cr-Commit-Position: refs/heads/master@{#427254}