Omnibox Style Cleanup

Following up from post-submission comments on
https://codereview.chromium.org/103783003/

TBR=sky

BUG=

Review URL: https://codereview.chromium.org/101043008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241766 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241766