Various fixes for aria-activedescendant.

third_party/WebKit/Source/modules/accessibility/AXObject.h

 /*
  * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 628 matching lines @@
     const AXObject* ariaHiddenRoot() const;
     bool computeIsInertOrAriaHidden(IgnoredReasons* = nullptr) const;
     bool isDescendantOfLeafNode() const;
     AXObject* leafNodeAncestor() const;
     bool isDescendantOfDisabledNode() const;
     const AXObject* disabledAncestor() const;
     bool lastKnownIsIgnoredValue();
     void setLastKnownIsIgnoredValue(bool);
     bool hasInheritedPresentationalRole() const;
     bool isPresentationalChild() const;
+    bool ancestorExposesActiveDescendant() const;

[dmazzoni, 2016/04/05 05:37:22]

This needs to be cached, check the other cached attributes in AXObject and how
they work. The cached values are reset whenever the tree changes in any way so
it's safe to cache. It saves us time when we scan the whole tree because we
don't have to keep walking up the ancestors of every node.

 
     //
     // Accessible name calculation
     //
 
     // Retrieves the accessible name of the object, an enum indicating where the name
     // was derived from, and a list of objects that were used to derive the name, if any.
     virtual String name(AXNameFrom&, AXObjectVector* nameObjects) const;
 
     typedef HeapVector<NameSource> NameSources;
@@ skipping 74 matching lines @@
     virtual InvalidState getInvalidState() const { return InvalidStateUndefined; }
     // Only used when invalidState() returns InvalidStateOther.
     virtual String ariaInvalidValue() const { return String(); }
     virtual String valueDescription() const { return String(); }
     virtual float valueForRange() const { return 0.0f; }
     virtual float maxValueForRange() const { return 0.0f; }
     virtual float minValueForRange() const { return 0.0f; }
     virtual String stringValue() const { return String(); }
 
     // ARIA attributes.
-    virtual AXObject* activeDescendant() const { return 0; }
+    virtual AXObject* activeDescendant() const { return nullptr; }
     virtual String ariaAutoComplete() const { return String(); }
     virtual String ariaDescribedByAttribute() const { return String(); }
     virtual void ariaFlowToElements(AXObjectVector&) const { }
     virtual void ariaControlsElements(AXObjectVector&) const { }
     virtual void ariaOwnsElements(AXObjectVector& owns) const { }
     virtual void ariaDescribedbyElements(AXObjectVector&) const { }
     virtual void ariaLabelledbyElements(AXObjectVector&) const { }
     virtual bool ariaHasPopup() const { return false; }
     virtual bool isEditable() const { return false; }
     bool isMultiline() const;
     virtual bool isRichlyEditable() const { return false; }
     virtual String ariaLabelledbyAttribute() const { return String(); }
     bool ariaPressedIsPresent() const;
     virtual AccessibilityRole ariaRoleAttribute() const { return UnknownRole; }
     virtual bool ariaRoleHasPresentationalChildren() const { return false; }
     virtual AXObject* ancestorForWhichThisIsAPresentationalChild() const { return 0; }
-    virtual bool shouldFocusActiveDescendant() const { return false; }
+    bool supportsActiveDescendant() const;
     bool supportsARIAAttributes() const;
     virtual bool supportsARIADragging() const { return false; }
     virtual bool supportsARIADropping() const { return false; }
     virtual bool supportsARIAFlowTo() const { return false; }
     virtual bool supportsARIAOwns() const { return false; }
     bool supportsRangeValue() const;
     virtual SortDirection getSortDirection() const { return SortDirectionUndefined; }
 
     // Returns 0-based index.
     int indexInParent() const;
@@ skipping 179 matching lines @@
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, object.predicate)
 
 } // namespace blink
 
 WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(blink::IgnoredReason);
 WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(blink::NameSource);
 WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(blink::DescriptionSource);
 
 #endif // AXObject_h