servo: Merge #18036 - Reject easings with trailing content in Servo_ParseEasing (from birtles:reject-easing-lists); r=hiro

Servo side changes for [Gecko bug 1385141](https://bugzilla.mozilla.org/show_bug.cgi?id=1385141).

Source-Repo: https://github.com/servo/servo
Source-Revision: 62dfee5e031253fe45cd203f628b5266ee81a71f

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 1aedfc1962cc25814ee89e3185c1cc2ba969485f

servo/ports/geckolib/glue.rs

@@ -1975,7 +1975,8 @@ pub extern "C" fn Servo_ParseEasing(easing: *const nsAString,
     let easing = unsafe { (*easing).to_string() };
     let mut input = ParserInput::new(&easing);
     let mut parser = Parser::new(&mut input);
-    let result = transition_timing_function::single_value::parse(&context, &mut parser);
+    let result =
+        parser.parse_entirely(|p| transition_timing_function::single_value::parse(&context, p));
     match result {
         Ok(parsed_easing) => {
             *output = parsed_easing.into();