Bug 1820280 - Be consistent for which URIs we expose chrome rules. r=dshin

Differential Revision: https://phabricator.services.mozilla.com/D171640

dom/base/Document.cpp

@@ -1349,7 +1349,7 @@ Document::Document(const char* aContentType)
       mInUnlinkOrDeletion(false),
       mHasHadScriptHandlingObject(false),
       mIsBeingUsedAsImage(false),
-      mDocURISchemeIsChrome(false),
+      mChromeRulesEnabled(false),
       mInChromeDocShell(false),
       mIsDevToolsDocument(false),
       mIsSyntheticDocument(false),
@@ -4023,7 +4023,7 @@ void Document::SetDocumentURI(nsIURI* aURI) {
   mDocumentURI = aURI;
   nsIURI* newBase = GetDocBaseURI();
 
-  mDocURISchemeIsChrome = aURI && IsChromeURI(aURI);
+  mChromeRulesEnabled = URLExtraData::ChromeRulesEnabled(aURI);
 
   bool equalBases = false;
   // Changing just the ref of a URI does not change how relative URIs would

dom/base/Document.h

@@ -2614,7 +2614,7 @@ class Document : public nsINode,
     return !mParentDocument && !mDisplayDocument;
   }
 
-  bool IsDocumentURISchemeChrome() const { return mDocURISchemeIsChrome; }
+  bool ChromeRulesEnabled() const { return mChromeRulesEnabled; }
 
   bool IsInChromeDocShell() const {
     const Document* root = this;
@@ -4650,8 +4650,8 @@ class Document : public nsINode,
   // True if we're an SVG document being used as an image.
   bool mIsBeingUsedAsImage : 1;
 
-  // True if our current document URI's scheme is chrome://
-  bool mDocURISchemeIsChrome : 1;
+  // True if our current document URI's scheme enables privileged CSS rules.
+  bool mChromeRulesEnabled : 1;
 
   // True if we're loaded in a chrome docshell.
   bool mInChromeDocShell : 1;

dom/base/nsINode.cpp

@@ -2977,12 +2977,11 @@ const RawServoSelectorList* nsINode::ParseSelectorList(
     // want to cache the "This is not a valid selector" result.
     //
     // NOTE(emilio): Off-hand, getting a CallerType here might seem like a
-    // better idea than using IsDocumentURISchemeChrome(), but that would mean
+    // better idea than using ChromeRulesEnabled(), but that would mean
     // that we'd need to key the selector cache by that.
-    // IsDocumentURISchemeChrome() gives us the same semantics as any inline
+    // ChromeRulesEnabled() gives us the same semantics as any inline
     // style associated to a document, which seems reasonable.
-    return Servo_SelectorList_Parse(&aSelectorString,
-                                    doc->IsDocumentURISchemeChrome())
+    return Servo_SelectorList_Parse(&aSelectorString, doc->ChromeRulesEnabled())
         .Consume();
   });
 

layout/base/nsCSSFrameConstructor.cpp

@@ -2716,7 +2716,7 @@ void nsCSSFrameConstructor::SetUpDocElementContainingBlock(
     if (isXUL) {
       return false;
     }
-    if (aDocElement->OwnerDoc()->IsDocumentURISchemeChrome() &&
+    if (aDocElement->OwnerDoc()->ChromeRulesEnabled() &&
         aDocElement->AsElement()->AttrValueIs(
             kNameSpaceID_None, nsGkAtoms::scrolling, nsGkAtoms::_false,
             eCaseMatters)) {

layout/style/PreferenceSheet.cpp

@@ -65,7 +65,7 @@ auto PreferenceSheet::PrefsKindFor(const Document& aDoc) -> PrefsKind {
     return PrefsKind::Chrome;
   }
 
-  if (aDoc.IsBeingUsedAsImage() && aDoc.IsDocumentURISchemeChrome()) {
+  if (aDoc.IsBeingUsedAsImage() && aDoc.ChromeRulesEnabled()) {
     return PrefsKind::Chrome;
   }
 

layout/style/URLExtraData.h

@@ -22,6 +22,10 @@
 namespace mozilla {
 
 struct URLExtraData {
+  static bool ChromeRulesEnabled(nsIURI* aURI) {
+    return aURI && (aURI->SchemeIs("chrome") || aURI->SchemeIs("resource"));
+  }
+
   URLExtraData(already_AddRefed<nsIURI> aBaseURI,
                already_AddRefed<nsIReferrerInfo> aReferrerInfo,
                already_AddRefed<nsIPrincipal> aPrincipal)
@@ -34,8 +38,7 @@ 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();
-    mChromeRulesEnabled = referrer && (referrer->SchemeIs("chrome") ||
-                                       referrer->SchemeIs("resource"));
+    mChromeRulesEnabled = ChromeRulesEnabled(referrer);
   }
 
   URLExtraData(nsIURI* aBaseURI, nsIReferrerInfo* aReferrerInfo,

layout/svg/SVGImageContext.cpp

@@ -37,7 +37,7 @@ void SVGImageContext::MaybeStoreContextPaint(SVGImageContext& aContext,
   }
 
   if (StaticPrefs::svg_embedder_prefers_color_scheme_content_enabled() ||
-      aPresContext.Document()->IsDocumentURISchemeChrome()) {
+      aPresContext.Document()->ChromeRulesEnabled()) {
     auto scheme = LookAndFeel::ColorSchemeForStyle(
         *aPresContext.Document(), aStyle.StyleUI()->mColorScheme.bits,
         ColorSchemeMode::Preferred);

servo/components/style/custom_properties.rs

@@ -146,7 +146,7 @@ impl CssEnvironment {
         if let Some(var) = ENVIRONMENT_VARIABLES.iter().find(|var| var.name == *name) {
             return Some((var.evaluator)(device));
         }
-        if !device.is_chrome_document() {
+        if !device.chrome_rules_enabled_for_document() {
             return None;
         }
         let var = CHROME_ENVIRONMENT_VARIABLES

servo/components/style/gecko/media_queries.rs

@@ -559,7 +559,7 @@ impl Device {
     /// This check is consistent with how we enable chrome rules for chrome:// and resource://
     /// stylesheets (and thus chrome:// documents).
     #[inline]
-    pub fn is_chrome_document(&self) -> bool {
-        self.document().mDocURISchemeIsChrome()
+    pub fn chrome_rules_enabled_for_document(&self) -> bool {
+        self.document().mChromeRulesEnabled()
     }
 }