ui: Time to empty the ui/test/ directory.

The remaining pieces in ui/test/ are used only by a unittest in ui/gfx/,
so in this patch we move these files into ui/gfx. This fixes the TODO in
ui/gfx/DEPS that was assigned to Ben.

BUG=None
TEST=ui_unittests
R=tony@chromium.org,ben@chromium.org

Review URL: https://codereview.chromium.org/147803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247866 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247866