Changeset 287683 in webkit

Timestamp:

Jan 6, 2022, 6:33:25 AM (5 years ago)

Author:

Alan Bujtas

Message:

Ensure that the top layer is always anchored to the RenderView
​https://bugs.webkit.org/show_bug.cgi?id=231292
<rdar://problem/83941854>

Reviewed by Simon Fraser.

Source/WebCore:

A fixed positioned block level box is not necessarily anchored to the RenderView (see canContainFixedPositionObjects).
This patch ensures that we skip those ancestors and return the RenderView as the containing block for the top layer content.

​https://fullscreen.spec.whatwg.org/#new-stacking-layer
"If the top layer position property computes to fixed, its containing block is the viewport, and the initial containing block otherwise."

• rendering/RenderObject.cpp:

(WebCore::RenderObject::containingBlock const):
(WebCore::containerForElement):

LayoutTests:

• TestExpectations: offsetFromAncestorContainer expects no transformed renderer in-between the

dialog and the RenderView's layer. It will go away with the layer re-parenting work.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/TestExpectations (modified) (1 diff)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderObject.cpp (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2022-01-06  Alan Bujtas  <zalan@apple.com>
+
+        Ensure that the top layer is always anchored to the RenderView
+        https://bugs.webkit.org/show_bug.cgi?id=231292
+        <rdar://problem/83941854>
+
+        Reviewed by Simon Fraser.
+
+        * TestExpectations: offsetFromAncestorContainer expects no transformed renderer in-between the
+        dialog and the RenderView's layer. It will go away with the layer re-parenting work.
+
 2022-01-05  Antoine Quint  <graouts@webkit.org>
 

trunk/LayoutTests/TestExpectations

@@ -2360 +2360 @@
 webkit.org/b/231292 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-parent-overflow-clip.html [ ImageOnlyFailure ]
 webkit.org/b/231292 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-parent-overflow-scroll.html [ ImageOnlyFailure ]
-webkit.org/b/231292 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-parent-transform.html [ ImageOnlyFailure ]
+# Needs layer re-parenting
+webkit.org/b/231292 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/top-layer-parent-transform.html [ Skip ]
 
 # Assertion failure in MessagePort::contextDestroyed, usually attributed to later tests

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2022-01-06  Alan Bujtas  <zalan@apple.com>
+
+        Ensure that the top layer is always anchored to the RenderView
+        https://bugs.webkit.org/show_bug.cgi?id=231292
+        <rdar://problem/83941854>
+
+        Reviewed by Simon Fraser.
+
+        A fixed positioned block level box is not necessarily anchored to the RenderView (see canContainFixedPositionObjects).
+        This patch ensures that we skip those ancestors and return the RenderView as the containing block for the top layer content.
+
+        https://fullscreen.spec.whatwg.org/#new-stacking-layer
+        "If the top layer position property computes to fixed, its containing block is the viewport, and the initial containing block otherwise."
+
+        * rendering/RenderObject.cpp:
+        (WebCore::RenderObject::containingBlock const):
+        (WebCore::containerForElement):
+
 2022-01-06  Jean-Yves Avenard  <jya@apple.com>
 

trunk/Source/WebCore/rendering/RenderObject.cpp

@@ -659 +659 @@
 RenderBlock* RenderObject::containingBlock() const
 {
-    auto containingBlockForRenderer = [](const RenderElement& renderer)
-    {
+    auto containingBlockForRenderer = [](const auto& renderer) -> RenderBlock* {
+        if (isInTopLayerOrBackdrop(renderer.style(), renderer.element()))
+            return &renderer.view();
         if (renderer.isAbsolutelyPositioned())
             return renderer.containingBlockForAbsolutePosition();
@@ -1475 +1476 @@
     if (!is<RenderElement>(renderer))
         return renderer.parent();
+    if (isInTopLayerOrBackdrop(renderer.style(), downcast<RenderElement>(renderer).element())) {
+        auto updateRepaintContainerSkippedFlagIfApplicable = [&] {
+            if (!repaintContainerSkipped)
+                return;
+            *repaintContainerSkipped = false;
+            if (repaintContainer == &renderer.view())
+                return;
+            for (auto& ancestor : ancestorsOfType<RenderElement>(renderer)) {
+                if (repaintContainer == &ancestor) {
+                    *repaintContainerSkipped = true;
+                    break;
+                }
+            }
+        };
+        updateRepaintContainerSkippedFlagIfApplicable();
+        return &renderer.view();
+    }
     auto position = renderer.style().position();
     if (position == PositionType::Static || position == PositionType::Relative || position == PositionType::Sticky)