Bug 1551040 - Allow resource:// stylesheets to use chrome-only rules. r=boris

We'll use it to use @-moz-document from plaintext.css.

Differential Revision: https://phabricator.services.mozilla.com/D101516

layout/style/StyleSheet.cpp

@@ -1142,7 +1142,7 @@ already_AddRefed<StyleSheet> StyleSheet::CreateEmptyChildSheet(
 // (3) The stylesheet is a chrome stylesheet, since those can use
 //     -moz-bool-pref, which needs to access the pref service, which is not
 //     threadsafe.
-static bool AllowParallelParse(css::Loader& aLoader, nsIURI* aSheetURI) {
+static bool AllowParallelParse(css::Loader& aLoader, URLExtraData* aUrlData) {
   // If the browser is recording CSS errors, we need to use the sequential path
   // because the parallel path doesn't support that.
   Document* doc = aLoader.GetDocument();
@@ -1157,7 +1157,7 @@ static bool AllowParallelParse(css::Loader& aLoader, nsIURI* aSheetURI) {
   //
   // Note that UA stylesheets can also use -moz-bool-pref, but those are always
   // parsed sync.
-  if (dom::IsChromeURI(aSheetURI)) {
+  if (aUrlData->ChromeRulesEnabled()) {
     return false;
   }
 
@@ -1179,7 +1179,7 @@ RefPtr<StyleSheetParsePromise> StyleSheet::ParseSheet(
                               : StyleAllowImportRules::Yes;
   const bool shouldRecordCounters =
       aLoader.GetDocument() && aLoader.GetDocument()->GetStyleUseCounters();
-  if (!AllowParallelParse(aLoader, GetSheetURI())) {
+  if (!AllowParallelParse(aLoader, Inner().mURLData)) {
     UniquePtr<StyleUseCounters> counters =
         shouldRecordCounters ? Servo_UseCounters_Create().Consume() : nullptr;
 

layout/style/URLExtraData.cpp

@@ -27,7 +27,7 @@ void URLExtraData::Init() {
   sDummyChrome =
       new URLExtraData(baseURI.forget(), referrerInfo.forget(),
                        NullPrincipal::CreateWithoutOriginAttributes());
-  sDummyChrome->mIsChrome = true;
+  sDummyChrome->mChromeRulesEnabled = true;
 }
 
 /* static */

layout/style/URLExtraData.h

@@ -34,7 +34,8 @@ struct URLExtraData {
     // When we hold the URI data of a style sheet, referrer is always
     // equal to the sheet URI.
     nsCOMPtr<nsIURI> referrer = mReferrerInfo->GetOriginalReferrer();
-    mIsChrome = referrer ? dom::IsChromeURI(referrer) : false;
+    mChromeRulesEnabled = referrer && (referrer->SchemeIs("chrome") ||
+                                       referrer->SchemeIs("resource"));
   }
 
   URLExtraData(nsIURI* aBaseURI, nsIReferrerInfo* aReferrerInfo,
@@ -48,6 +49,8 @@ struct URLExtraData {
   nsIReferrerInfo* ReferrerInfo() const { return mReferrerInfo; }
   nsIPrincipal* Principal() const { return mPrincipal; }
 
+  bool ChromeRulesEnabled() const { return mChromeRulesEnabled; }
+
   static URLExtraData* Dummy() {
     MOZ_ASSERT(sDummy);
     return sDummy;
@@ -73,8 +76,7 @@ struct URLExtraData {
   nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
   nsCOMPtr<nsIPrincipal> mPrincipal;
 
-  // True if referrer is a chrome:// URI.
-  bool mIsChrome;
+  bool mChromeRulesEnabled;
 
   static StaticRefPtr<URLExtraData> sDummy;
   static StaticRefPtr<URLExtraData> sDummyChrome;

servo/components/style/parser.rs

@@ -140,7 +140,7 @@ impl<'a> ParserContext<'a> {
     /// Returns whether chrome-only rules should be parsed.
     #[inline]
     pub fn chrome_rules_enabled(&self) -> bool {
-        self.url_data.is_chrome() || self.stylesheet_origin == Origin::User
+        self.url_data.chrome_rules_enabled() || self.stylesheet_origin == Origin::User
     }
 
     /// Whether we're in a user-agent stylesheet or chrome rules are enabled.

servo/components/style/selector_parser.rs

@@ -75,7 +75,7 @@ impl<'a> SelectorParser<'a> {
     /// Whether we're parsing selectors in a stylesheet that has chrome
     /// privilege.
     pub fn chrome_rules_enabled(&self) -> bool {
-        self.url_data.map_or(false, |d| d.is_chrome()) || self.stylesheet_origin == Origin::User
+        self.url_data.map_or(false, |d| d.chrome_rules_enabled()) || self.stylesheet_origin == Origin::User
     }
 }
 

servo/components/style/stylesheets/mod.rs

@@ -156,8 +156,8 @@ impl UrlExtraData {
 
     /// True if this URL scheme is chrome.
     #[inline]
-    pub fn is_chrome(&self) -> bool {
-        self.as_ref().mIsChrome
+    pub fn chrome_rules_enabled(&self) -> bool {
+        self.as_ref().mChromeRulesEnabled
     }
 
     /// Create a reference to this `UrlExtraData` from a reference to pointer.
@@ -215,7 +215,7 @@ impl fmt::Debug for UrlExtraData {
 
         formatter
             .debug_struct("URLExtraData")
-            .field("is_chrome", &self.is_chrome())
+            .field("chrome_rules_enabled", &self.chrome_rules_enabled())
             .field(
                 "base",
                 &DebugURI(self.as_ref().mBaseURI.raw::<structs::nsIURI>()),