servo: Merge #17173 - Stop parsing @supports rules before Delimiter::Bang (from Manishearth:supports-fixes); r=upsuper

Fixes #15482

Shorthand parsing uses `parse_entirely`, so we have to ask it to stop before the `!important`.

An alternate fix is to not use `parse_entirely` there and ensuring that all callers of `PropertyDeclaration::parse_into()` check that the input is exhausted. Two of the three callers do that anyway because they check for `!important`.

We also weren't checking for the end of the parser for `CSS.supports()`.

Source-Repo: https://github.com/servo/servo
Source-Revision: eaa01223a7add99ce4cc241b686100856b7594d6

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 271b84c5cb44b18f04d1c887ae98ec5154ab8817

servo/components/style/stylesheets/supports_rule.rs

@@ -4,7 +4,7 @@
 
 //! [@supports rules](https://drafts.csswg.org/css-conditional-3/#at-supports)
 
-use cssparser::{parse_important, Parser, SourceLocation, Token};
+use cssparser::{Delimiter, parse_important, Parser, SourceLocation, Token};
 use parser::ParserContext;
 use properties::{PropertyId, PropertyDeclaration, SourcePropertyDeclaration};
 use shared_lock::{DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
@@ -263,7 +263,10 @@ impl Declaration {
         let mut input = Parser::new(&self.val);
         let context = ParserContext::new_with_rule_type(cx, Some(CssRuleType::Style));
         let mut declarations = SourcePropertyDeclaration::new();
-        let res = PropertyDeclaration::parse_into(&mut declarations, id, &context, &mut input);
+        let res = input.parse_until_before(Delimiter::Bang, |input| {
+            PropertyDeclaration::parse_into(&mut declarations, id, &context, input)
+                .map_err(|_| ())
+        });
         let _ = input.try(parse_important);
         res.is_ok() && input.is_exhausted()
     }

servo/ports/geckolib/glue.rs

@@ -2298,7 +2298,7 @@ pub extern "C" fn Servo_CSSSupports2(property: *const nsACString,
 pub extern "C" fn Servo_CSSSupports(cond: *const nsACString) -> bool {
     let condition = unsafe { cond.as_ref().unwrap().as_str_unchecked() };
     let mut input = Parser::new(&condition);
-    let cond = parse_condition_or_declaration(&mut input);
+    let cond = input.parse_entirely(|i| parse_condition_or_declaration(i));
     if let Ok(cond) = cond {
         let url_data = unsafe { dummy_url_data() };
         let reporter = RustLogReporter;