style: Introduce Chrome UI privilege for parsers

The motivation is that Chrome XBL stylesheets can be parsed under author
level, but we allow some event-state pseudo classes like
:-moz-handled-clicktoplay to be used.

Also synchronize the privilege of pseudo classes in
non_ts_pseudo_class_list.rs and nsCSSPseudoClassList.h (except :fullscreen).

MozReview-Commit-ID: 8fUjjC8hbQO

components/script/dom/cssstylerule.rs

@@ -93,6 +93,7 @@ impl CSSStyleRuleMethods for CSSStyleRule {
         let parser = SelectorParser {
             stylesheet_origin: Origin::Author,
             namespaces: &namespaces,
+            url_data: None,
         };
         let mut css_parser = CssParserInput::new(&*value);
         let mut css_parser = CssParser::new(&mut css_parser);

components/style/gecko/non_ts_pseudo_class_list.rs

@@ -45,7 +45,7 @@ macro_rules! apply_non_ts_list {
             bare: [
                 ("unresolved", Unresolved, unresolved, IN_UNRESOLVED_STATE, _),
                 ("-moz-table-border-nonzero", MozTableBorderNonzero, mozTableBorderNonzero, _, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
-                ("-moz-browser-frame", MozBrowserFrame, mozBrowserFrame, _, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-browser-frame", MozBrowserFrame, mozBrowserFrame, _, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
                 ("link", Link, link, IN_UNVISITED_STATE, _),
                 ("any-link", AnyLink, anyLink, IN_VISITED_OR_UNVISITED_STATE, _),
                 ("visited", Visited, visited, IN_VISITED_STATE, _),
@@ -61,29 +61,29 @@ macro_rules! apply_non_ts_list {
                 ("indeterminate", Indeterminate, indeterminate, IN_INDETERMINATE_STATE, _),
                 ("-moz-devtools-highlighted", MozDevtoolsHighlighted, mozDevtoolsHighlighted, IN_DEVTOOLS_HIGHLIGHTED_STATE, _),
                 ("-moz-styleeditor-transitioning", MozStyleeditorTransitioning, mozStyleeditorTransitioning, IN_STYLEEDITOR_TRANSITIONING_STATE, _),
-                // TODO(emilio): Needs pref check for
+                // TODO(emilio): Needs pref check for full-screen-api.unprefix.enabled!
-                // full-screen-api.unprefix.enabled!
+                // TODO(TYLin): Needs to use CSS_PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME?
                 ("fullscreen", Fullscreen, fullscreen, IN_FULLSCREEN_STATE, _),
                 ("-moz-full-screen", MozFullScreen, mozFullScreen, IN_FULLSCREEN_STATE, _),
                 // TODO(emilio): This is inconsistently named (the capital R).
                 ("-moz-focusring", MozFocusRing, mozFocusRing, IN_FOCUSRING_STATE, _),
                 ("-moz-broken", MozBroken, mozBroken, IN_BROKEN_STATE, _),
                 ("-moz-loading", MozLoading, mozLoading, IN_LOADING_STATE, _),
-                ("-moz-suppressed", MozSuppressed, mozSuppressed, IN_SUPPRESSED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-suppressed", MozSuppressed, mozSuppressed, IN_SUPPRESSED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
                 ("-moz-has-dir-attr", MozHasDirAttr, mozHasDirAttr, IN_HAS_DIR_ATTR_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
                 ("-moz-dir-attr-ltr", MozDirAttrLTR, mozDirAttrLTR, IN_HAS_DIR_ATTR_LTR_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
                 ("-moz-dir-attr-rtl", MozDirAttrRTL, mozDirAttrRTL, IN_HAS_DIR_ATTR_RTL_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
                 ("-moz-dir-attr-like-auto", MozDirAttrLikeAuto, mozDirAttrLikeAuto, IN_HAS_DIR_ATTR_LIKE_AUTO_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
-                ("-moz-autofill", MozAutofill, mozAutofill, IN_AUTOFILL_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-autofill", MozAutofill, mozAutofill, IN_AUTOFILL_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
-                ("-moz-autofill-preview", MozAutofillPreview, mozAutofillPreview, IN_AUTOFILL_PREVIEW_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-autofill-preview", MozAutofillPreview, mozAutofillPreview, IN_AUTOFILL_PREVIEW_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
 
-                ("-moz-handler-clicktoplay", MozHandlerClickToPlay, mozHandlerClickToPlay, IN_HANDLER_CLICK_TO_PLAY_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-clicktoplay", MozHandlerClickToPlay, mozHandlerClickToPlay, IN_HANDLER_CLICK_TO_PLAY_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
-                ("-moz-handler-vulnerable-updatable", MozHandlerVulnerableUpdatable, mozHandlerVulnerableUpdatable, IN_HANDLER_VULNERABLE_UPDATABLE_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-vulnerable-updatable", MozHandlerVulnerableUpdatable, mozHandlerVulnerableUpdatable, IN_HANDLER_VULNERABLE_UPDATABLE_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
-                ("-moz-handler-vulnerable-no-update", MozHandlerVulnerableNoUpdate, mozHandlerVulnerableNoUpdate, IN_HANDLER_VULNERABLE_NO_UPDATE_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-vulnerable-no-update", MozHandlerVulnerableNoUpdate, mozHandlerVulnerableNoUpdate, IN_HANDLER_VULNERABLE_NO_UPDATE_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
 
-                ("-moz-handler-disabled", MozHandlerDisabled, mozHandlerDisabled, IN_HANDLER_DISABLED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-disabled", MozHandlerDisabled, mozHandlerDisabled, IN_HANDLER_DISABLED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
-                ("-moz-handler-blocked", MozHandlerBlocked, mozHandlerBlocked, IN_HANDLER_BLOCKED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-blocked", MozHandlerBlocked, mozHandlerBlocked, IN_HANDLER_BLOCKED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
-                ("-moz-handler-crashed", MozHandlerCrashed, mozHandlerCrashed, IN_HANDLER_CRASHED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-handler-crashed", MozHandlerCrashed, mozHandlerCrashed, IN_HANDLER_CRASHED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
                 ("-moz-math-increment-script-level", MozMathIncrementScriptLevel, mozMathIncrementScriptLevel, IN_INCREMENT_SCRIPT_LEVEL_STATE, _),
 
                 ("required", Required, required, IN_REQUIRED_STATE, _),
@@ -103,7 +103,7 @@ macro_rules! apply_non_ts_list {
                 ("-moz-meter-sub-optimum", MozMeterSubOptimum, mozMeterSubOptimum, IN_SUB_OPTIMUM_STATE, _),
                 ("-moz-meter-sub-sub-optimum", MozMeterSubSubOptimum, mozMeterSubSubOptimum, IN_SUB_SUB_OPTIMUM_STATE, _),
 
-                ("-moz-user-disabled", MozUserDisabled, mozUserDisabled, IN_USER_DISABLED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-user-disabled", MozUserDisabled, mozUserDisabled, IN_USER_DISABLED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
 
                 ("-moz-first-node", MozFirstNode, firstNode, _, _),
                 ("-moz-last-node", MozLastNode, lastNode, _, _),

components/style/gecko/selector_parser.rs

@@ -18,9 +18,12 @@ pub use gecko::pseudo_element::{PseudoElement, EAGER_PSEUDOS, EAGER_PSEUDO_COUNT
 pub use gecko::snapshot::SnapshotMap;
 
 bitflags! {
+    // See NonTSPseudoClass::is_enabled_in()
     flags NonTSPseudoClassFlag: u8 {
-        // See NonTSPseudoClass::is_internal()
         const PSEUDO_CLASS_ENABLED_IN_UA_SHEETS = 1 << 0,
+        const PSEUDO_CLASS_ENABLED_IN_CHROME = 1 << 1,
+        const PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME =
+            PSEUDO_CLASS_ENABLED_IN_UA_SHEETS.bits | PSEUDO_CLASS_ENABLED_IN_CHROME.bits,
     }
 }
 
@@ -122,14 +125,14 @@ impl SelectorMethods for NonTSPseudoClass {
 
 
 impl NonTSPseudoClass {
-    /// A pseudo-class is internal if it can only be used inside
+    /// Returns true if this pseudo-class is enabled under the context of
-    /// user agent style sheets.
+    /// the given flag.
-    pub fn is_internal(&self) -> bool {
+    fn is_enabled_in(&self, flag: NonTSPseudoClassFlag) -> bool {
         macro_rules! check_flag {
             (_) => (false);
-            ($flags:expr) => ($flags.contains(PSEUDO_CLASS_ENABLED_IN_UA_SHEETS));
+            ($flags:expr) => ($flags.contains(flag));
         }
-        macro_rules! pseudo_class_check_internal {
+        macro_rules! pseudo_class_check_is_enabled_in {
             (bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
             string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
             keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
@@ -141,7 +144,7 @@ impl NonTSPseudoClass {
                 }
             }
         }
-        apply_non_ts_list!(pseudo_class_check_internal)
+        apply_non_ts_list!(pseudo_class_check_is_enabled_in)
     }
 
     /// https://drafts.csswg.org/selectors-4/#useraction-pseudos
@@ -263,6 +266,21 @@ impl ::selectors::SelectorImpl for SelectorImpl {
     }
 }
 
+impl<'a> SelectorParser<'a> {
+    fn is_pseudo_class_enabled(&self,
+                               pseudo_class: &NonTSPseudoClass)
+                               -> bool {
+        let enabled_in_ua = pseudo_class.is_enabled_in(PSEUDO_CLASS_ENABLED_IN_UA_SHEETS);
+        let enabled_in_chrome = pseudo_class.is_enabled_in(PSEUDO_CLASS_ENABLED_IN_CHROME);
+        if !enabled_in_ua && !enabled_in_chrome {
+            true
+        } else {
+            (enabled_in_ua && self.in_user_agent_stylesheet()) ||
+            (enabled_in_chrome && self.in_chrome_stylesheet())
+        }
+    }
+}
+
 impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     type Impl = SelectorImpl;
     type Error = StyleParseError<'i>;
@@ -286,7 +304,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
             }
         }
         let pseudo_class = apply_non_ts_list!(pseudo_class_parse);
-        if !pseudo_class.is_internal() || self.in_user_agent_stylesheet() {
+        if self.is_pseudo_class_enabled(&pseudo_class) {
             Ok(pseudo_class)
         } else {
             Err(SelectorParseError::UnexpectedIdent(name).into())
@@ -331,7 +349,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
             }
         }
         let pseudo_class = apply_non_ts_list!(pseudo_class_string_parse);
-        if !pseudo_class.is_internal() || self.in_user_agent_stylesheet() {
+        if self.is_pseudo_class_enabled(&pseudo_class) {
             Ok(pseudo_class)
         } else {
             Err(SelectorParseError::UnexpectedIdent(name).into())

components/style/selector_parser.rs

@@ -11,7 +11,7 @@ use selectors::Element;
 use selectors::parser::SelectorList;
 use std::fmt::Debug;
 use style_traits::ParseError;
-use stylesheets::{Origin, Namespaces};
+use stylesheets::{Origin, Namespaces, UrlExtraData};
 
 /// A convenient alias for the type that represents an attribute value used for
 /// selector parser implementation.
@@ -52,6 +52,9 @@ pub struct SelectorParser<'a> {
     pub stylesheet_origin: Origin,
     /// The namespace set of the stylesheet.
     pub namespaces: &'a Namespaces,
+    /// The extra URL data of the stylesheet, which is used to look up
+    /// whether we are parsing a chrome:// URL style sheet.
+    pub url_data: Option<&'a UrlExtraData>,
 }
 
 impl<'a> SelectorParser<'a> {
@@ -65,6 +68,7 @@ impl<'a> SelectorParser<'a> {
         let parser = SelectorParser {
             stylesheet_origin: Origin::Author,
             namespaces: &namespaces,
+            url_data: None,
         };
         let mut input = ParserInput::new(input);
         SelectorList::parse(&parser, &mut CssParser::new(&mut input))
@@ -74,6 +78,12 @@ impl<'a> SelectorParser<'a> {
     pub fn in_user_agent_stylesheet(&self) -> bool {
         matches!(self.stylesheet_origin, Origin::UserAgent)
     }
+
+    /// Whether we're parsing selectors in a stylesheet that has chrome
+    /// privilege.
+    pub fn in_chrome_stylesheet(&self) -> bool {
+        self.url_data.map_or(false, |d| d.is_chrome())
+    }
 }
 
 /// This enumeration determines if a pseudo-element is eagerly cascaded or not.

components/style/stylesheets/mod.rs

@@ -70,6 +70,11 @@ impl UrlExtraData {
         // TODO
         "(stylo: not supported)"
     }
+
+    /// True if this URL scheme is chrome.
+    pub fn is_chrome(&self) -> bool {
+        self.mIsChrome
+    }
 }
 
 // XXX We probably need to figure out whether we should mark Eq here.

components/style/stylesheets/rule_parser.rs

@@ -507,6 +507,7 @@ impl<'a, 'b, 'i> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b> {
         let selector_parser = SelectorParser {
             stylesheet_origin: self.stylesheet_origin,
             namespaces: self.context.namespaces.unwrap(),
+            url_data: Some(self.context.url_data),
         };
 
         let location = get_location_with_offset(input.current_source_location(),

components/url/lib.rs

@@ -85,6 +85,10 @@ impl ServoUrl {
         scheme == "https" || scheme == "wss"
     }
 
+    pub fn is_chrome(&self) -> bool {
+        self.scheme() == "chrome"
+    }
+
     pub fn as_str(&self) -> &str {
         self.0.as_str()
     }

tests/unit/style/parsing/selectors.rs

@@ -14,6 +14,7 @@ fn parse_selector<'i, 't>(input: &mut Parser<'i, 't>) -> Result<SelectorList<Sel
     let parser = SelectorParser {
         stylesheet_origin: Origin::UserAgent,
         namespaces: &ns,
+        url_data: None,
     };
     SelectorList::parse(&parser, input)
 }