Bug 1687127 - Remove dom.expose-incomplete-stylesheets. r=boris

Shipped in 84 (bug 1673885).

Differential Revision: https://phabricator.services.mozilla.com/D102090

dom/base/LinkStyle.cpp

@@ -70,11 +70,10 @@ LinkStyle::LinkStyle()
 LinkStyle::~LinkStyle() { LinkStyle::SetStyleSheet(nullptr); }
 
 StyleSheet* LinkStyle::GetSheetForBindings() const {
-  if (!StaticPrefs::dom_expose_incomplete_stylesheets() && mStyleSheet &&
-      !mStyleSheet->IsComplete()) {
-    return nullptr;
+  if (mStyleSheet && mStyleSheet->IsComplete()) {
+    return mStyleSheet;
   }
-  return mStyleSheet;
+  return nullptr;
 }
 
 void LinkStyle::GetTitleAndMediaForElement(const Element& aSelf,
@@ -215,8 +214,7 @@ Result<LinkStyle::Update, nsresult> LinkStyle::DoUpdateStyleSheet(
     //
     // We want to do this even if updates are disabled, since otherwise a sheet
     // with a stale linking element pointer will be hanging around -- not good!
-    if (mStyleSheet->IsComplete() ||
-        StaticPrefs::dom_expose_incomplete_stylesheets()) {
+    if (mStyleSheet->IsComplete()) {
       if (aOldShadowRoot) {
         aOldShadowRoot->RemoveStyleSheet(*mStyleSheet);
       } else {
@@ -252,8 +250,7 @@ Result<LinkStyle::Update, nsresult> LinkStyle::DoUpdateStyleSheet(
   }
 
   if (mStyleSheet) {
-    if (mStyleSheet->IsComplete() ||
-        StaticPrefs::dom_expose_incomplete_stylesheets()) {
+    if (mStyleSheet->IsComplete()) {
       if (thisContent.IsInShadowTree()) {
         ShadowRoot* containingShadow = thisContent.GetContainingShadow();
         // Could be null only during unlink.

layout/style/Loader.cpp

@@ -1702,7 +1702,7 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadInlineStyle(
   if (auto* linkStyle = LinkStyle::FromNodeOrNull(aInfo.mContent)) {
     linkStyle->SetStyleSheet(sheet);
   }
-  if (StaticPrefs::dom_expose_incomplete_stylesheets() || sheet->IsComplete()) {
+  if (sheet->IsComplete()) {
     InsertSheetInTree(*sheet, aInfo.mContent);
   }
 
@@ -1805,7 +1805,7 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
   if (auto* linkStyle = LinkStyle::FromNodeOrNull(aInfo.mContent)) {
     linkStyle->SetStyleSheet(sheet);
   }
-  if (StaticPrefs::dom_expose_incomplete_stylesheets() || sheet->IsComplete()) {
+  if (sheet->IsComplete()) {
     InsertSheetInTree(*sheet, aInfo.mContent);
   }
 

layout/style/SharedStyleSheetCache.cpp

@@ -342,12 +342,6 @@ void SharedStyleSheetCache::LoadCompletedInternal(
       // Insert the sheet into the tree now the sheet has loaded, but only if
       // the sheet is still relevant, and if this is a top-level sheet.
       const bool needInsertIntoTree = [&] {
-        if (StaticPrefs::dom_expose_incomplete_stylesheets()) {
-          // No need to do that, it's already done. This is technically a bit
-          // racy, but having to reload if you hit an in-progress load while
-          // switching the pref from about:config is not a big deal.
-          return false;
-        }
         if (!data->mLoader->GetDocument()) {
           // Not a document load, nothing to do.
           return false;

modules/libpref/init/StaticPrefList.yaml

@@ -2214,16 +2214,6 @@
   value: true
   mirror: always
 
-# Whether the LinkStyle.sheet and DocumentOrShadowRoot.styleSheets accessor
-# exposes in-progress-loading stylesheets.
-#
-# Historical behavior is `true`, but other browsers (and also a bit of common
-# sense) match `false`.
-- name: dom.expose-incomplete-stylesheets
-  type: bool
-  value: false
-  mirror: always
-
 # Whether the Large-Allocation header is enabled.
 - name: dom.largeAllocationHeader.enabled
   type: bool