tor-browser

commit b5ac7753b2fa5c3b8dc7294acec0b906d995e791
parent 1e00d9deee01443f17a61406f8dca13ddf7cecab
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Tue, 11 Nov 2025 22:42:32 +0000

Bug 1998572 - Ensure masks/clip-path isolate for backdrop-filter if needed. r=gw

Differential Revision: https://phabricator.services.mozilla.com/D272111

Diffstat:
M
layout/generic/nsIFrame.cpp
 | 
8
++++----
M
layout/painting/nsDisplayList.cpp
 | 
11
++++++++---
M
layout/painting/nsDisplayList.h
 | 
8
+++++---
M
testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path-2.html.ini
 | 
4
+++-
D
testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path.html.ini
 | 
5
-----

5 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/layout/generic/nsIFrame.cpp b/layout/generic/nsIFrame.cpp
@@ -3583,14 +3583,15 @@ void nsIFrame::BuildDisplayListForStackingContext(
       // We don't need to isolate the root frame.
       return reasons;
     }
-    // Elements with a view-transition name also form a backdrop-root.
+    // Elements with a view-transition name also form a backdrop-root. Same for
+    // masks / clip-path.
     // See https://www.w3.org/TR/css-view-transitions-1/#named-and-transitioning
     // and https://github.com/w3c/csswg-drafts/issues/11772
     const bool hasViewTransitionName =
         style.StyleUIReset()->HasViewTransitionName() &&
         !style.IsRootElementStyle();
     if ((disp->mWillChange.bits & StyleWillChangeBits::BACKDROP_ROOT) ||
-        hasViewTransitionName) {
+        hasViewTransitionName || usingMask) {
       reasons |= StackingContextBits::ContainsBackdropFilter;
     }
     if (!combines3DTransformWithAncestors) {
@@ -3686,9 +3687,8 @@ void nsIFrame::BuildDisplayListForStackingContext(
           clipForMask.isSome()
               ? nsDisplayItem::ContainerASRType::Constant
               : nsDisplayItem::ContainerASRType::AncestorOfContained,
-          usingBackdropFilter);
+          usingBackdropFilter, ShouldForceIsolation());
       createdContainer = true;
-      MarkAsIsolated();
     }
 
     // TODO(miko): We could probably create a wraplist here and avoid creating
diff --git a/layout/painting/nsDisplayList.cpp b/layout/painting/nsDisplayList.cpp
@@ -8130,10 +8130,12 @@ static void ComputeMaskGeometry(PaintFramesParams& aParams) {
 nsDisplayMasksAndClipPaths::nsDisplayMasksAndClipPaths(
     nsDisplayListBuilder* aBuilder, nsIFrame* aFrame, nsDisplayList* aList,
     const ActiveScrolledRoot* aActiveScrolledRoot,
-    ContainerASRType aContainerASRType, bool aWrapsBackdropFilter)
+    ContainerASRType aContainerASRType, bool aWrapsBackdropFilter,
+    bool aForceIsolation)
     : nsDisplayEffectsBase(aBuilder, aFrame, aList, aActiveScrolledRoot,
-                           aContainerASRType, true),
-      mWrapsBackdropFilter(aWrapsBackdropFilter) {
+                           aContainerASRType, /* aClearClipChain = */ true),
+      mWrapsBackdropFilter(aWrapsBackdropFilter),
+      mForceIsolation(aForceIsolation) {
   MOZ_COUNT_CTOR(nsDisplayMasksAndClipPaths);
 
   nsPresContext* presContext = mFrame->PresContext();
@@ -8452,6 +8454,9 @@ bool nsDisplayMasksAndClipPaths::CreateWebRenderCommands(
     wr::StackingContextParams params;
     params.clip = wr::WrStackingContextClip::ClipChain(clip->id);
     params.opacity = opacity.ptrOr(nullptr);
+    if (mForceIsolation) {
+      params.flags |= wr::StackingContextFlags::FORCED_ISOLATION;
+    }
     if (mWrapsBackdropFilter) {
       params.flags |= wr::StackingContextFlags::WRAPS_BACKDROP_FILTER;
     }
diff --git a/layout/painting/nsDisplayList.h b/layout/painting/nsDisplayList.h
@@ -6092,12 +6092,13 @@ class nsDisplayMasksAndClipPaths final : public nsDisplayEffectsBase {
                              nsDisplayList* aList,
                              const ActiveScrolledRoot* aActiveScrolledRoot,
                              ContainerASRType aContainerASRType,
-                             bool aWrapsBackdropFilter);
+                             bool aWrapsBackdropFilter, bool aForceIsolation);
   nsDisplayMasksAndClipPaths(nsDisplayListBuilder* aBuilder,
                              const nsDisplayMasksAndClipPaths& aOther)
       : nsDisplayEffectsBase(aBuilder, aOther),
         mDestRects(aOther.mDestRects.Clone()),
-        mWrapsBackdropFilter(aOther.mWrapsBackdropFilter) {
+        mWrapsBackdropFilter(aOther.mWrapsBackdropFilter),
+        mForceIsolation(aOther.mForceIsolation) {
     MOZ_COUNT_CTOR(nsDisplayMasksAndClipPaths);
   }
 
@@ -6162,7 +6163,8 @@ class nsDisplayMasksAndClipPaths final : public nsDisplayEffectsBase {
   NS_DISPLAY_ALLOW_CLONING()
 
   nsTArray<nsRect> mDestRects;
-  bool mWrapsBackdropFilter;
+  bool mWrapsBackdropFilter : 1;
+  bool mForceIsolation : 1;
 };
 
 class nsDisplayBackdropFilters final : public nsDisplayWrapList {
diff --git a/testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path-2.html.ini b/testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path-2.html.ini
@@ -1,2 +1,4 @@
 [backdrop-filter-backdrop-root-clip-path-2.html]
-  expected: FAIL
+  expected:
+    if useDrawSnapshot: FAIL
+    PASS
diff --git a/testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path.html.ini b/testing/web-platform/meta/css/filter-effects/backdrop-filter-backdrop-root-clip-path.html.ini
@@ -1,5 +0,0 @@
-[backdrop-filter-backdrop-root-clip-path.html]
-  expected:
-    if (os == "win") and not debug: [PASS, FAIL]
-    if useDrawSnapshot: PASS
-    FAIL