AX: optimize accessibilityIsIgnored computation

https://bugs.webkit.org/show_bug.cgi?id=262733
rdar://problem/116541936

Reviewed by Tyler Wilcock.

We currently traverse the ancestor hierarchy three times to compute each of
isAXHidden, isPresentationalChildOfAriaRole, and isDescendantOfBarrenParent
—all of which we gather to compute accessibility is ignored.

This patch combines those ancestor traversals into one, using
generateIsIgnoredFromParentData. This saves up to roughly 20% of samples for
accessibilityIsIgnored across various sites.

* Source/WebCore/accessibility/AccessibilityNodeObject.cpp:
(WebCore::AccessibilityNodeObject::canHaveChildren const):
(WebCore::AccessibilityNodeObject::computeAccessibilityIsIgnored const):
* Source/WebCore/accessibility/AccessibilityObject.cpp:
(WebCore::AccessibilityObject::isARIAHidden const):
(WebCore::AccessibilityObject::isAXHidden const):
(WebCore::AccessibilityObject::defaultObjectInclusion const):
(WebCore::AccessibilityObject::setIsIgnoredFromParentDataForChild):
(WebCore::AccessibilityObject::isPresentationalChildOfAriaRole const): Deleted.
* Source/WebCore/accessibility/AccessibilityObject.h:
(WebCore::AccessibilityObject::hasImplicitGenericRole const):
* Source/WebCore/accessibility/AccessibilityRenderObject.cpp:
(WebCore::AccessibilityRenderObject::computeAccessibilityIsIgnored const):

Canonical link: https://commits.webkit.org/269313@main

Source/WebCore/accessibility/AccessibilityNodeObject.cpp

@@ -591,7 +591,10 @@ bool AccessibilityNodeObject::canHaveChildren() const
     // Elements that should not have children.
     switch (roleValue()) {
     case AccessibilityRole::Button:
+#if !USE(ATSPI)
+    // GTK/ATSPI layout tests expect popup buttons to have children.
     case AccessibilityRole::PopUpButton:
+#endif
     case AccessibilityRole::Checkbox:
     case AccessibilityRole::RadioButton:
     case AccessibilityRole::Tab:
@@ -655,9 +658,6 @@ bool AccessibilityNodeObject::computeAccessibilityIsIgnored() const
         return false;
     if (decision == AccessibilityObjectInclusion::IgnoreObject)
         return true;
-    // If this element is within a parent that cannot have children, it should not be exposed.
-    if (isDescendantOfBarrenParent())
-        return true;
 
     auto role = roleValue();
     return role == AccessibilityRole::Ignored || role == AccessibilityRole::Unknown;

Source/WebCore/accessibility/AccessibilityObject.cpp

@@ -3915,6 +3915,11 @@ bool AccessibilityObject::accessibilityIsIgnoredByDefault() const
     return defaultObjectInclusion() == AccessibilityObjectInclusion::IgnoreObject;
 }
 
+bool AccessibilityObject::isARIAHidden() const
+{
+    return equalLettersIgnoringASCIICase(getAttribute(aria_hiddenAttr), "true"_s) && !isFocused();
+}
+
 // ARIA component of hidden definition.
 // https://www.w3.org/TR/wai-aria/#dfn-hidden
 bool AccessibilityObject::isAXHidden() const
@@ -3923,7 +3928,7 @@ bool AccessibilityObject::isAXHidden() const
         return false;
 
     return Accessibility::findAncestor<AccessibilityObject>(*this, true, [] (const AccessibilityObject& object) {
-        return equalLettersIgnoringASCIICase(object.getAttribute(aria_hiddenAttr), "true"_s) && !object.isFocused();
+        return object.isARIAHidden();
     }) != nullptr;
 }
 
@@ -3969,10 +3974,16 @@ AccessibilityObjectInclusion AccessibilityObject::defaultObjectInclusion() const
     }
 
     bool useParentData = !m_isIgnoredFromParentData.isNull();
-    if (useParentData ? m_isIgnoredFromParentData.isAXHidden : isAXHidden())
+    if (useParentData && (m_isIgnoredFromParentData.isAXHidden || m_isIgnoredFromParentData.isPresentationalChildOfAriaRole))
         return AccessibilityObjectInclusion::IgnoreObject;
 
-    if (useParentData ? m_isIgnoredFromParentData.isPresentationalChildOfAriaRole : isPresentationalChildOfAriaRole())
+    if (isARIAHidden())
+        return AccessibilityObjectInclusion::IgnoreObject;
+
+    bool ignoreARIAHidden = isFocused();
+    if (Accessibility::findAncestor<AccessibilityObject>(*this, false, [&] (const auto& object) {
+        return (!ignoreARIAHidden && object.isARIAHidden()) || object.ariaRoleHasPresentationalChildren() || !object.canHaveChildren();
+    }))
         return AccessibilityObjectInclusion::IgnoreObject;
 
     // Include <dialog> elements and elements with role="dialog".
@@ -4332,13 +4343,6 @@ bool AccessibilityObject::ariaRoleHasPresentationalChildren() const
     }
 }
 
-bool AccessibilityObject::isPresentationalChildOfAriaRole() const
-{
-    return Accessibility::findAncestor(*this, false, [] (const auto& ancestor) {
-        return ancestor.ariaRoleHasPresentationalChildren();
-    });
-}
-
 void AccessibilityObject::setIsIgnoredFromParentDataForChild(AccessibilityObject* child)
 {
     if (!child)
@@ -4350,9 +4354,20 @@ void AccessibilityObject::setIsIgnoredFromParentDataForChild(AccessibilityObject
         result.isPresentationalChildOfAriaRole = m_isIgnoredFromParentData.isPresentationalChildOfAriaRole || ariaRoleHasPresentationalChildren();
         result.isDescendantOfBarrenParent = m_isIgnoredFromParentData.isDescendantOfBarrenParent || !canHaveChildren();
     } else {
-        result.isAXHidden = child->isAXHidden();
-        result.isPresentationalChildOfAriaRole = child->isPresentationalChildOfAriaRole();
-        result.isDescendantOfBarrenParent = child->isDescendantOfBarrenParent();
+        if (child->isARIAHidden())
+            result.isAXHidden = true;
+
+        bool ignoreARIAHidden = child->isFocused();
+        for (auto* object = child->parentObject(); object; object = object->parentObject()) {
+            if (!result.isAXHidden && !ignoreARIAHidden && object->isARIAHidden())
+                result.isAXHidden = true;
+
+            if (!result.isPresentationalChildOfAriaRole && object->ariaRoleHasPresentationalChildren())
+                result.isPresentationalChildOfAriaRole = true;
+
+            if (!result.isDescendantOfBarrenParent && !object->canHaveChildren())
+                result.isDescendantOfBarrenParent = true;
+        }
     }
 
     child->setIsIgnoredFromParentData(result);

Source/WebCore/accessibility/AccessibilityObject.h

@@ -264,6 +264,7 @@ class AccessibilityObject : public AXCoreObject, public CanMakeWeakPtr<Accessibi
     void recomputeIsIgnored();
     AccessibilityObjectInclusion defaultObjectInclusion() const;
     bool accessibilityIsIgnoredByDefault() const;
+    bool isARIAHidden() const;
 
     bool isShowingValidationMessage() const;
     String validationMessage() const;
@@ -361,7 +362,6 @@ 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(); }
-    bool isPresentationalChildOfAriaRole() const;
     bool ariaRoleHasPresentationalChildren() const;
     bool inheritsPresentationalRole() const override { return false; }
 

Source/WebCore/accessibility/AccessibilityRenderObject.cpp

@@ -1066,10 +1066,6 @@ bool AccessibilityRenderObject::computeAccessibilityIsIgnored() const
     if (decision == AccessibilityObjectInclusion::IgnoreObject)
         return true;
 
-    // If this element is within a parent that cannot have children, it should not be exposed.
-    if (isDescendantOfBarrenParent())
-        return true;    
-
     if (roleValue() == AccessibilityRole::Ignored)
         return true;