servo: Merge #17035 - Allow text to be in background shorthand (from upsuper:bug1188074); r=heycam

Servo side change of [bug 1188074](https://bugzilla.mozilla.org/show_bug.cgi?id=1188074).

Source-Repo: https://github.com/servo/servo
Source-Revision: 3016a036503b541f2e4b5693b496ebdc0f5ca411

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 7d7451a0b1038039ed1d660625f74e91a64bc9df

servo/components/style/properties/shorthand/background.mako.rs

@@ -72,13 +72,6 @@
                     if ${name}.is_none() {
                         if let Ok(value) = input.try(|input| background_${name}::single_value
                                                                                ::parse(context, input)) {
-                            % if name == "clip" and product == "gecko":
-                            // "text" value of background-clip should not be part of background
-                            // shorthand per current spec and impls.
-                            if value == background_clip::single_value::SpecifiedValue::text {
-                                return Err(());
-                            }
-                            % endif
                             ${name} = Some(value);
                             continue
                         }