Omnibox: Turn on Reorder Mode By Default

Reorder mode was evaluated as a 30% experiment in Beta.  Based on the
results ( see crbug 273149 ), we've decided to launch it.  We're going
to do a staged rollout.  This change enables reorder mode by default.
We're going to use the variations server to limit reorder mode to (for
now) be on for 90% of users.

BUG=339808

Review URL: https://codereview.chromium.org/147123009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249314 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249314
Pull out and test BoundedScrollView.

Part of an effort to increase reliability of message center.

BUG=NONE

Review URL: https://codereview.chromium.org/138793008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249315 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249315