gtk: Disable menu icons again.

This re-does my previous change to set gtk-menu-images to 0.
I'm going to check in a Chrome change first so that Views
menu items with icons will override this setting:

I'm also leaving out the earlier change to remove horizontal
spacing, since it makes the items looked cramped and doesn't
get along well with items that still have icons.

Still need to find a way to get rid of the excess space on
the left of the omnibox menu (might be a GTK+ bug; looks
like we're still getting the padding even though the icon is
hidden) and the left of the wrench menu.

TEST=built and used it

Review URL:

Change-Id: I068194b66016b934b01738552ff62c89146135b0
1 file changed