Consistently decorate pref values sent to the settings UI code

Pref values are provided to the settings UI code by three different
classes. Each decorates the values slightly differently, adding
different metadata fields or none at all. This CL makes the classes
use a consistent decoration with identically named metadata fields,
simplifying the handling of pref values on the JS side.

BUG=104955


Review URL: https://chromiumcodereview.appspot.com/10834109

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150527 0039d316-1c4b-4281-b951-d872f2087c98
11 files changed