gtk: Move AutocompletePopupViewGtk/autocomplete_popup_view_gtk.* to ui/gtk/omnibox directory.
- Rename AutocompletePopupViewGtk to OmniboxPopupViewGtk.
- Move autocomplete_popup_view_gtk.* to omnibox_popup_view_gtk.*
BUG=80186
TEST=None
R=pkasting@chromium.org,evan@chromium.org
Review URL: http://codereview.chromium.org/7264012
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90687 0039d316-1c4b-4281-b951-d872f2087c98