Adds assets for an experimental Omnibox search/arrow button.

Assets made by designer bettes@. The images were run through pngcrush per the instructions in chrome/theme/app/README.

BUG=311269, 304859
R=oshima@chromium.org

Review URL: https://codereview.chromium.org/55923002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232438 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232438