Handful of related instant changes:

. Makes the code for running the promo more real. We're not ready to
  flip it on yet, so it isn't enabled.
. Nukes verbatim from about:flags and instead randomly chooses
  verbatim/predictive when the user opts in. We're doing this to try
  and see if we get feedback as to which one folks like more. Windows
  preferences shows you which one you get (by way of an obscure
  label). I'll change gtk do to that shortly too.
. Adds metrics.

And a couple of random style issues I encountered in some files.

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/5023001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@66187 0039d316-1c4b-4281-b951-d872f2087c98