Make AXCoreObject::visibleChildren, AXCoreObject::isPresentationalChi…

…ldOfAriaRole, and AXCoreObject::ariaRoleHasPresentationalChildren work for display:contents elements

https://bugs.webkit.org/show_bug.cgi?id=255371
rdar://problem/107962942

Reviewed by Chris Fleizach and Andres Gonzalez.

None of these methods inherently require a renderer, but are still only
implemented for AccessibilityRenderObject, meaning they won't work for
display:contents elements. This patch fixes this by moving the
implementations to the appropriate base class for each method.

Other significant changes worth mentioning:
  1. `visibleChildren` for ARIA listboxes had a bug where it selected
     children that were `isOffScreen` rather than `!isOffScreen`.
  2. NSAccessibilityVisibleChildrenAttribute was removed as a supported
     attribute for menus and menu bars since we always return nil for
     this combination of role and attribute.

* LayoutTests/accessibility/presentational-children-expected.txt:
* LayoutTests/accessibility/presentational-children.html:
* Source/WebCore/accessibility/AccessibilityListBox.cpp:
(WebCore::AccessibilityListBox::visibleChildren):
* Source/WebCore/accessibility/AccessibilityListBox.h:
* Source/WebCore/accessibility/AccessibilityNodeObject.cpp:
(WebCore::AccessibilityNodeObject::visibleChildren):
* Source/WebCore/accessibility/AccessibilityNodeObject.h:
* Source/WebCore/accessibility/AccessibilityObject.cpp:
(WebCore::AccessibilityObject::ariaRoleHasPresentationalChildren const):
(WebCore::AccessibilityObject::isPresentationalChildOfAriaRole const):
* Source/WebCore/accessibility/AccessibilityObject.h:
(WebCore::AccessibilityObject::isPresentationalChildOfAriaRole const): Deleted.
(WebCore::AccessibilityObject::ariaRoleHasPresentationalChildren const): Deleted.
* Source/WebCore/accessibility/AccessibilityObjectInterface.h:
* Source/WebCore/accessibility/AccessibilityRenderObject.cpp:
(WebCore::AccessibilityRenderObject::isPresentationalChildOfAriaRole const): Deleted.
(WebCore::AccessibilityRenderObject::ariaRoleHasPresentationalChildren const): Deleted.
(WebCore::AccessibilityRenderObject::ariaListboxVisibleChildren): Deleted.
(WebCore::AccessibilityRenderObject::visibleChildren): Deleted.
* Source/WebCore/accessibility/AccessibilityRenderObject.h:
* Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.cpp:
(WebCore::AXIsolatedObject::initializeProperties):
* Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.h:
* Source/WebCore/accessibility/mac/WebAccessibilityObjectWrapperMac.mm:
(-[WebAccessibilityObjectWrapper accessibilityAttributeValue:]):

Canonical link: https://commits.webkit.org/263025@main

LayoutTests/accessibility/presentational-children-expected.txt

@@ -6,6 +6,7 @@ On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE
 button childrenCount: 0
 checkbox childrenCount: 0
 img childrenCount: 0
+img childrenCount: 0
 menuitemcheckbox childrenCount: 0
 menuitemradio childrenCount: 0
 meter childrenCount: 0

LayoutTests/accessibility/presentational-children.html

@@ -8,6 +8,7 @@
   <div role="button" tabindex="0" class="ex"><div>a</div><div>b</div></div>
   <div role="checkbox" tabindex="0" class="ex"><div>a</div><div>b</div></div>
   <div role="img" tabindex="0" class="ex"><div>a</div><div>b</div></div>
+  <div role="img" tabindex="0" class="ex" style="display:contents"><div style="display:contents">a</div><div>b</div></div>
   <div role="menu">
     <div role="menuitemcheckbox" tabindex="0" class="ex"><div>a</div><div>b</div></div>
     <div role="menuitemradio" tabindex="0" class="ex"><div>a</div><div>b</div></div>

Source/WebCore/accessibility/AccessibilityListBox.cpp

@@ -114,18 +114,22 @@ void AccessibilityListBox::selectedChildren(AccessibilityChildrenVector& result)
     }    
 }
 
-void AccessibilityListBox::visibleChildren(AccessibilityChildrenVector& result)
+AXCoreObject::AccessibilityChildrenVector AccessibilityListBox::visibleChildren()
 {
-    ASSERT(result.isEmpty());
-
+    ASSERT(!m_renderer || is<RenderListBox>(m_renderer.get()));
+    auto* listBox = dynamicDowncast<RenderListBox>(m_renderer.get());
+    if (!listBox)
+        return { };
+
     if (!childrenInitialized())
         addChildren();
 
-    unsigned length = m_children.size();
-    for (unsigned i = 0; i < length; i++) {
-        if (downcast<RenderListBox>(*m_renderer).listIndexIsVisible(i))
+    AccessibilityChildrenVector result;
+    for (unsigned i = 0; i < m_children.size(); i++) {
+        if (listBox->listIndexIsVisible(i))
             result.append(m_children[i]);
     }
+    return result;
 }
 
 AccessibilityObject* AccessibilityListBox::listBoxOptionAccessibilityObject(HTMLElement* element) const

Source/WebCore/accessibility/AccessibilityListBox.h

@@ -42,7 +42,7 @@ class AccessibilityListBox final : public AccessibilityRenderObject {
     AccessibilityRole roleValue() const override { return AccessibilityRole::ListBox; }
 
     void selectedChildren(AccessibilityChildrenVector&) override;
-    void visibleChildren(AccessibilityChildrenVector&) override;
+    AccessibilityChildrenVector visibleChildren() final;
 
     void addChildren() override;
 

Source/WebCore/accessibility/AccessibilityNodeObject.cpp

@@ -546,6 +546,24 @@ bool AccessibilityNodeObject::canHaveChildren() const
     }
 }
 
+AXCoreObject::AccessibilityChildrenVector AccessibilityNodeObject::visibleChildren()
+{
+    // Only listboxes are asked for their visible children.
+    // Native list boxes would be AccessibilityListBoxes, so only check for aria list boxes.
+    if (ariaRoleAttribute() != AccessibilityRole::ListBox)
+        return { };
+
+    if (!childrenInitialized())
+        addChildren();
+
+    AccessibilityChildrenVector result;
+    for (const auto& child : children()) {
+        if (!child->isOffScreen())
+            result.append(child);
+    }
+    return result;
+}
+
 bool AccessibilityNodeObject::computeAccessibilityIsIgnored() const
 {
 #ifndef NDEBUG

Source/WebCore/accessibility/AccessibilityNodeObject.h

@@ -156,6 +156,7 @@ class AccessibilityNodeObject : public AccessibilityObject {
     void clearChildren() override;
     void updateChildrenIfNecessary() override;
     bool canHaveChildren() const override;
+    AccessibilityChildrenVector visibleChildren() override;
     bool isDescendantOfBarrenParent() const override;
     void updateOwnedChildren();
     AccessibilityObject* ownerParentObject() const;

Source/WebCore/accessibility/AccessibilityObject.cpp

@@ -3907,6 +3907,27 @@ bool AccessibilityObject::isActiveDescendantOfFocusedContainer() const
     return false;
 }
 
+bool AccessibilityObject::ariaRoleHasPresentationalChildren() const
+{
+    switch (ariaRoleAttribute()) {
+    case AccessibilityRole::Button:
+    case AccessibilityRole::Slider:
+    case AccessibilityRole::Image:
+    case AccessibilityRole::ProgressIndicator:
+    case AccessibilityRole::SpinButton:
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool AccessibilityObject::isPresentationalChildOfAriaRole() const
+{
+    return Accessibility::findAncestor(*this, false, [] (const auto& ancestor) {
+        return ancestor.ariaRoleHasPresentationalChildren();
+    });
+}
+
 void AccessibilityObject::setIsIgnoredFromParentDataForChild(AccessibilityObject* child)
 {
     if (!child)

Source/WebCore/accessibility/AccessibilityObject.h

@@ -361,8 +361,8 @@ class AccessibilityObject : public AXCoreObject, public CanMakeWeakPtr<Accessibi
     virtual AccessibilityRole ariaRoleAttribute() const { return AccessibilityRole::Unknown; }
     bool hasExplicitGenericRole() const { return ariaRoleAttribute() == AccessibilityRole::Generic; }
     bool hasImplicitGenericRole() const { return roleValue() == AccessibilityRole::Generic && !hasExplicitGenericRole(); }
-    virtual bool isPresentationalChildOfAriaRole() const { return false; }
-    virtual bool ariaRoleHasPresentationalChildren() const { return false; }
+    bool isPresentationalChildOfAriaRole() const;
+    bool ariaRoleHasPresentationalChildren() const;
     bool inheritsPresentationalRole() const override { return false; }
 
     // Accessibility Text
@@ -517,7 +517,7 @@ class AccessibilityObject : public AXCoreObject, public CanMakeWeakPtr<Accessibi
 
     void selectedChildren(AccessibilityChildrenVector&) override { }
     void setSelectedChildren(const AccessibilityChildrenVector&) override { }
-    void visibleChildren(AccessibilityChildrenVector&) override { }
+    AccessibilityChildrenVector visibleChildren() override { return { }; }
     virtual bool shouldFocusActiveDescendant() const { return false; }
     AccessibilityObject* activeDescendant() const override { return nullptr; }
 

Source/WebCore/accessibility/AccessibilityObjectInterface.h

@@ -1250,7 +1250,7 @@ class AXCoreObject : public ThreadSafeRefCounted<AXCoreObject> {
     bool canHaveSelectedChildren() const;
     virtual void selectedChildren(AccessibilityChildrenVector&) = 0;
     virtual void setSelectedChildren(const AccessibilityChildrenVector&) = 0;
-    virtual void visibleChildren(AccessibilityChildrenVector&) = 0;
+    virtual AccessibilityChildrenVector visibleChildren() = 0;
     AccessibilityChildrenVector tabChildren();
     virtual AXCoreObject* activeDescendant() const = 0;
     bool isDescendantOfObject(const AXCoreObject*) const;

Source/WebCore/accessibility/AccessibilityRenderObject.cpp

@@ -2708,31 +2708,6 @@ bool AccessibilityRenderObject::inheritsPresentationalRole() const
     return false;
 }
 
-bool AccessibilityRenderObject::isPresentationalChildOfAriaRole() const
-{
-    // Walk the parent chain looking for a parent that has presentational children
-    AccessibilityObject* parent;
-    for (parent = parentObject(); parent && !parent->ariaRoleHasPresentationalChildren(); parent = parent->parentObject())
-    { }
-
-    return parent;
-}
-
-bool AccessibilityRenderObject::ariaRoleHasPresentationalChildren() const
-{
-    switch (m_ariaRole) {
-    case AccessibilityRole::Button:
-    case AccessibilityRole::Slider:
-    case AccessibilityRole::Image:
-    case AccessibilityRole::ProgressIndicator:
-    case AccessibilityRole::SpinButton:
-    // case SeparatorRole:
-        return true;
-    default:
-        return false;
-    }
-}
-
 void AccessibilityRenderObject::addImageMapChildren()
 {
     RenderBoxModelObject* cssBox = renderBoxModelObject();
@@ -3133,28 +3108,6 @@ void AccessibilityRenderObject::selectedChildren(AccessibilityChildrenVector& re
     }
 }
 
-void AccessibilityRenderObject::ariaListboxVisibleChildren(AccessibilityChildrenVector& result)      
-{
-    if (!childrenInitialized())
-        addChildren();
-
-    for (const auto& child : children()) {
-        if (child->isOffScreen())
-            result.append(child);
-    }
-}
-
-void AccessibilityRenderObject::visibleChildren(AccessibilityChildrenVector& result)
-{
-    ASSERT(result.isEmpty());
-
-    // Only listboxes are asked for their visible children.
-    // Native list boxes would be AccessibilityListBoxes, so only check for aria list boxes.
-    if (ariaRoleAttribute() != AccessibilityRole::ListBox)
-        return;
-    return ariaListboxVisibleChildren(result);
-}
-
 void AccessibilityRenderObject::setAccessibleName(const AtomString& name)
 {
     // Setting the accessible name can store the value in the DOM

Source/WebCore/accessibility/AccessibilityRenderObject.h

@@ -88,8 +88,6 @@ class AccessibilityRenderObject : public AccessibilityNodeObject {
     AccessibilityObject* titleUIElement() const override;
 
     bool supportsARIAOwns() const override;
-    bool isPresentationalChildOfAriaRole() const override;
-    bool ariaRoleHasPresentationalChildren() const override;
 
     // Should be called on the root accessibility object to kick off a hit test.
     AXCoreObject* accessibilityHitTest(const IntPoint&) const override;
@@ -132,7 +130,6 @@ class AccessibilityRenderObject : public AccessibilityNodeObject {
     void addChildren() override;
     bool canHaveChildren() const override;
     void selectedChildren(AccessibilityChildrenVector&) override;
-    void visibleChildren(AccessibilityChildrenVector&) override;
     bool shouldFocusActiveDescendant() const override;
     AccessibilityObject* activeDescendant() const override;
 
@@ -193,7 +190,6 @@ class AccessibilityRenderObject : public AccessibilityNodeObject {
 private:
     bool isAccessibilityRenderObject() const final { return true; }
     void ariaListboxSelectedChildren(AccessibilityChildrenVector&);
-    void ariaListboxVisibleChildren(AccessibilityChildrenVector&);
     bool isAllowedChildOfTree() const;
     String positionalDescriptionForMSAA() const;
     PlainTextRange documentBasedSelectedTextRange() const;

Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.cpp

@@ -241,9 +241,10 @@ void AXIsolatedObject::initializeProperties(const Ref<AccessibilityObject>& axOb
     if (object.isImage())
         setProperty(AXPropertyName::EmbeddedImageDescription, object.embeddedImageDescription().isolatedCopy());
 
-    AccessibilityChildrenVector visibleChildren;
-    object.visibleChildren(visibleChildren);
-    setObjectVectorProperty(AXPropertyName::VisibleChildren, visibleChildren);
+    // On macOS, we only advertise support for the visible children attribute for listboxes.
+    if (object.isListBox())
+        setObjectVectorProperty(AXPropertyName::VisibleChildren, object.visibleChildren());
+
     setObjectVectorProperty(AXPropertyName::LinkedObjects, object.linkedObjects());
 
     if (object.isSpinButton()) {

Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.h

@@ -294,7 +294,7 @@ class AXIsolatedObject final : public AXCoreObject {
     String language() const override { return stringAttributeValue(AXPropertyName::Language); }
     void selectedChildren(AccessibilityChildrenVector& children) override { fillChildrenVectorForProperty(AXPropertyName::SelectedChildren, children); }
     void setSelectedChildren(const AccessibilityChildrenVector&) override;
-    void visibleChildren(AccessibilityChildrenVector& children) override { fillChildrenVectorForProperty(AXPropertyName::VisibleChildren, children); }
+    AccessibilityChildrenVector visibleChildren() override { return tree()->objectsForIDs(vectorAttributeValue<AXID>(AXPropertyName::VisibleChildren)); }
     AtomString tagName() const override;
     const AccessibilityChildrenVector& children(bool updateChildrenIfNeeded = true) override;
     void updateChildrenIfNecessary() override;

Source/WebCore/accessibility/mac/WebAccessibilityObjectWrapperMac.mm

@@ -1003,15 +1003,13 @@ - (NSArray*)accessibilityAttributeNames
     static NeverDestroyed menuBarAttrs = [] {
         auto tempArray = adoptNS([[NSMutableArray alloc] initWithArray:commonMenuAttrs.get().get()]);
         [tempArray addObject:NSAccessibilitySelectedChildrenAttribute];
-        [tempArray addObject:NSAccessibilityVisibleChildrenAttribute];
         [tempArray addObject:NSAccessibilityTitleUIElementAttribute];
         [tempArray addObject:NSAccessibilityOrientationAttribute];
         return tempArray;
     }();
     static NeverDestroyed menuAttrs = [] {
         auto tempArray = adoptNS([[NSMutableArray alloc] initWithArray:commonMenuAttrs.get().get()]);
         [tempArray addObject:NSAccessibilitySelectedChildrenAttribute];
-        [tempArray addObject:NSAccessibilityVisibleChildrenAttribute];
         [tempArray addObject:NSAccessibilityTitleUIElementAttribute];
         [tempArray addObject:NSAccessibilityOrientationAttribute];
         return tempArray;
@@ -1615,11 +1613,8 @@ - (id)accessibilityAttributeValue:(NSString*)attributeName
     }
 
     if ([attributeName isEqualToString: NSAccessibilityVisibleChildrenAttribute]) {
-        if (backingObject->isListBox()) {
-            AccessibilityObject::AccessibilityChildrenVector visibleChildrenCopy;
-            backingObject->visibleChildren(visibleChildrenCopy);
-            return makeNSArray(visibleChildrenCopy);
-        }
+        if (backingObject->isListBox())
+            return makeNSArray(backingObject->visibleChildren());
 
         if (backingObject->isList())
             return [self accessibilityAttributeValue:NSAccessibilityChildrenAttribute];