Moves the out-of-process parts from chrome/browser/importer into
chrome/utility/importer. The majority here are simple moves, mostly
into chrome/utility/importer and a few into chrome/common/importer.

A few places required splitting files up to put some in different
parts of browser|common|utility. These were:
- chrome/browser/favicon ReencodeFavicon -> utility (it depends on
Blink, so should only be in child processes)
- history::VisitSource as used by ImporterBridge -> new similar enum
in importer_data_types that's remapped once it's in the browser
process
- LogImporterUseToMetrics split out to importer_uma in browser.

Adds chrome/utility/importer/OWNERS identical to chrome/browser/importer.

Existing DEPS disallows both utility->browser and browser->utility.

TBR=gab@chromium.org, jam@chromium.org, joth@chromium.org, jschuh@chromium.org, thestig@chromium.org

BUG=254672,237249

Review URL: https://codereview.chromium.org/18501013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@211858 0039d316-1c4b-4281-b951-d872f2087c98