Make importers read urls to private type and convert to history type in browser

That parts that will live in utility (the actual importers) work on
ImporterURLRow instead of history::URLRow, and once it's in-process in
in_process_importer_bridge, they're converted to history::URLRow to
be passed on to the profile code.

In preference to https://codereview.chromium.org/17956003/.

[email protected]
BUG=254672

Review URL: https://codereview.chromium.org/18080009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@209239 0039d316-1c4b-4281-b951-d872f2087c98
16 files changed