Add a pref name for share targets, and store their manifest data.
Adds a dictionary pref name, to store sites with manifests that
contain the share_url_template field; the key is the site origin, and
value is the value of share_url_template in the site's manifest.
Reads manifests after they have been parsed, for the share_url_template,
and stores the site and value under the pref name added.
Follow-up CL will read the pref store for the pref name added, and read
share targets in chrome/browser/webshare/share_service_impl.cc.
NO_DEPENDENCY_CHECKS=true
BUG=668389
Review-Url: https://codereview.chromium.org/2639463002
Cr-Commit-Position: refs/heads/master@{#447721}
9 files changed
