9 files changed, 16 insertions, 66 deletions
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index ec676ca921..34cfc6b59a 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -3563,10 +3563,6 @@ nsCSSFrameConstructor::FindHTMLData(Element* aElement,
     return nullptr;
   }
 
-  if (aTag == nsGkAtoms::details && !HTMLDetailsElement::IsDetailsEnabled()) {
-    return nullptr;
-  }
-
   static const FrameConstructionDataByTag sHTMLData[] = {
     SIMPLE_TAG_CHAIN(img, nsCSSFrameConstructor::FindImgData),
     SIMPLE_TAG_CHAIN(mozgeneratedcontentimage,
@@ -5788,7 +5784,7 @@ nsCSSFrameConstructor::AddFrameConstructionItemsInternal(nsFrameConstructorState
   // ::before and ::after); we always want to create "internal" anonymous
   // content.
   auto* details = HTMLDetailsElement::FromContentOrNull(parent);
-  if (details && details->IsDetailsEnabled() && !details->Open() &&
+  if (details && !details->Open() &&
       (!aContent->IsRootOfNativeAnonymousSubtree() ||
        aContent->IsGeneratedContentContainerForBefore() ||
        aContent->IsGeneratedContentContainerForAfter())) {
@@ -5956,7 +5952,7 @@ nsCSSFrameConstructor::AddFrameConstructionItemsInternal(nsFrameConstructorState
   }
 
   FrameConstructionItem* item = nullptr;
-  if (details && details->IsDetailsEnabled() && details->Open()) {
+  if (details && details->Open()) {
     auto* summary = HTMLSummaryElement::FromContentOrNull(aContent);
     if (summary && summary->IsMainSummary()) {
       // If details is open, the main summary needs to be rendered as if it is
diff --git a/layout/build/nsLayoutStatics.cpp b/layout/build/nsLayoutStatics.cpp
index 0f4560afea..27236e3f4f 100644
--- a/layout/build/nsLayoutStatics.cpp
+++ b/layout/build/nsLayoutStatics.cpp
@@ -412,8 +412,6 @@ nsLayoutStatics::Shutdown()
 
   DisplayItemClip::Shutdown();
 
-  CustomElementRegistry::XPCOMShutdown();
-
   CacheObserver::Shutdown();
 
   PromiseDebugging::Shutdown();
diff --git a/layout/generic/crashtests/crashtests.list b/layout/generic/crashtests/crashtests.list
index 183556ab93..a3c0d62c68 100644
--- a/layout/generic/crashtests/crashtests.list
+++ b/layout/generic/crashtests/crashtests.list
@@ -606,19 +606,19 @@ pref(layout.css.grid.enabled,true) load 1225376.html
 pref(layout.css.grid.enabled,true) load 1225592.html
 load 1229437-1.html
 load 1229437-2.html
-pref(dom.details_element.enabled,true) load details-containing-only-text.html
-pref(dom.details_element.enabled,true) load details-display-none-summary-1.html
-pref(dom.details_element.enabled,true) load details-display-none-summary-2.html
-pref(dom.details_element.enabled,true) load details-display-none-summary-3.html
-pref(dom.details_element.enabled,true) load details-open-overflow-auto.html
-pref(dom.details_element.enabled,true) load details-open-overflow-hidden.html
-pref(dom.details_element.enabled,true) load details-three-columns.html
+load details-containing-only-text.html
+load details-display-none-summary-1.html
+load details-display-none-summary-2.html
+load details-display-none-summary-3.html
+load details-open-overflow-auto.html
+load details-open-overflow-hidden.html
+load details-three-columns.html
 load first-letter-638937-1.html
 load first-letter-638937-2.html
 load flex-nested-abspos-1.html
 pref(dom.meta-viewport.enabled,true) test-pref(font.size.inflation.emPerLine,15) asserts(0-100) load font-inflation-762332.html # bug 762332
 load outline-on-frameset.xhtml
-pref(dom.details_element.enabled,true) load summary-position-out-of-flow.html
+load summary-position-out-of-flow.html
 load text-overflow-bug666751-1.html
 load text-overflow-bug666751-2.html
 load text-overflow-bug670564.xhtml
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
index abf687c9bd..afc4ed96f4 100644
--- a/layout/generic/nsContainerFrame.cpp
+++ b/layout/generic/nsContainerFrame.cpp
@@ -1890,12 +1890,10 @@ nsContainerFrame::RenumberFrameAndDescendants(int32_t* aOrdinal,
   }
 
   // Do not renumber list for summary elements.
-  if (HTMLDetailsElement::IsDetailsEnabled()) {
-    HTMLSummaryElement* summary =
-      HTMLSummaryElement::FromContent(kid->GetContent());
-    if (summary && summary->IsMainSummary()) {
-      return false;
-    }
+  HTMLSummaryElement* summary =
+    HTMLSummaryElement::FromContent(kid->GetContent());
+  if (summary && summary->IsMainSummary()) {
+    return false;
   }
 
   bool kidRenumberedABullet = false;
diff --git a/layout/reftests/details-summary/disabled-no-summary-ref.html b/layout/reftests/details-summary/disabled-no-summary-ref.html
deleted file mode 100644
index 6ecdbcdc0a..0000000000
--- a/layout/reftests/details-summary/disabled-no-summary-ref.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<!DOCTYPE html>
-<!-- Any copyright is dedicated to the Public Domain.
-   - http://creativecommons.org/publicdomain/zero/1.0/ -->
-
-<html>
-  <body>
-    <div>
-      <p>This is the details.</p>
-    </div>
-  </body>
-</html>
diff --git a/layout/reftests/details-summary/disabled-single-summary-ref.html b/layout/reftests/details-summary/disabled-single-summary-ref.html
deleted file mode 100644
index f643af6dcd..0000000000
--- a/layout/reftests/details-summary/disabled-single-summary-ref.html
+++ /dev/null
@@ -1,12 +0,0 @@
-<!DOCTYPE html>
-<!-- Any copyright is dedicated to the Public Domain.
-   - http://creativecommons.org/publicdomain/zero/1.0/ -->
-
-<html>
-  <body>
-    <div>
-      <div>Summary</div>
-      <p>This is the details.</p>
-    </div>
-  </body>
-</html>
diff --git a/layout/reftests/details-summary/reftest-stylo.list b/layout/reftests/details-summary/reftest-stylo.list
index e23b1206b2..2c6ec0d7b9 100644
--- a/layout/reftests/details-summary/reftest-stylo.list
+++ b/layout/reftests/details-summary/reftest-stylo.list
@@ -1,10 +1,4 @@
 # DO NOT EDIT! This is a auto-generated temporary list for Stylo testing
-default-preferences pref(dom.details_element.enabled,true)
-
-# Disable <details> and <summary>
-pref(dom.details_element.enabled,false) == single-summary.html single-summary.html
-pref(dom.details_element.enabled,false) == open-single-summary.html open-single-summary.html
-pref(dom.details_element.enabled,false) == no-summary.html no-summary.html
 
 # Basic <summary> handling
 == multiple-summary.html multiple-summary.html
diff --git a/layout/reftests/details-summary/reftest.list b/layout/reftests/details-summary/reftest.list
index 92b1404b52..e96581ad45 100644
--- a/layout/reftests/details-summary/reftest.list
+++ b/layout/reftests/details-summary/reftest.list
@@ -1,10 +1,3 @@
-default-preferences pref(dom.details_element.enabled,true)
-
-# Disable <details> and <summary>
-pref(dom.details_element.enabled,false) == single-summary.html disabled-single-summary-ref.html
-pref(dom.details_element.enabled,false) == open-single-summary.html disabled-single-summary-ref.html
-pref(dom.details_element.enabled,false) == no-summary.html disabled-no-summary-ref.html
-
 # Basic <summary> handling
 == multiple-summary.html single-summary.html
 == open-multiple-summary.html open-multiple-summary-ref.html
diff --git a/layout/style/nsLayoutStylesheetCache.cpp b/layout/style/nsLayoutStylesheetCache.cpp
index e8c6d09d7e..0e6bc35eeb 100644
--- a/layout/style/nsLayoutStylesheetCache.cpp
+++ b/layout/style/nsLayoutStylesheetCache.cpp
@@ -122,11 +122,6 @@ nsLayoutStylesheetCache::UASheet()
 StyleSheet*
 nsLayoutStylesheetCache::HTMLSheet()
 {
-  if (!mHTMLSheet) {
-    LoadSheetURL("resource://gre-resources/html.css",
-                 &mHTMLSheet, eAgentSheetFeatures, eCrash);
-  }
-
   return mHTMLSheet;
 }
 
@@ -322,6 +317,8 @@ nsLayoutStylesheetCache::nsLayoutStylesheetCache(StyleBackendType aType)
   // per-profile, since they're profile-invariant.
   LoadSheetURL("resource://gre-resources/counterstyles.css",
                &mCounterStylesSheet, eAgentSheetFeatures, eCrash);
+  LoadSheetURL("resource://gre-resources/html.css",
+               &mHTMLSheet, eAgentSheetFeatures, eCrash);
   LoadSheetURL("chrome://global/content/minimal-xul.css",
                &mMinimalXULSheet, eAgentSheetFeatures, eCrash);
   LoadSheetURL("resource://gre-resources/quirk.css",
@@ -382,8 +379,6 @@ nsLayoutStylesheetCache::For(StyleBackendType aType)
     //                               "layout.css.example-pref.enabled");
     Preferences::RegisterCallback(&DependentPrefChanged,
                                   "layout.css.grid.enabled");
-    Preferences::RegisterCallback(&DependentPrefChanged,
-                                  "dom.details_element.enabled");
   }
 
   return cache;
@@ -555,7 +550,6 @@ nsLayoutStylesheetCache::DependentPrefChanged(const char* aPref, void* aData)
                   gStyleCache_Servo ? &gStyleCache_Servo->sheet_ : nullptr);
 
   INVALIDATE(mUASheet);  // for layout.css.grid.enabled
-  INVALIDATE(mHTMLSheet); // for dom.details_element.enabled
 
 #undef INVALIDATE
 }