Add interface to get relative bounding box rect of AX objects.

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * 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.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 238 matching lines @@
     if (!m_layoutObject || !m_layoutObject->isBox())
         return 0;
 
     LayoutBox* box = toLayoutBox(m_layoutObject);
     if (!box->canBeScrolledAndHasScrollableArea())
         return 0;
 
     return box->getScrollableArea();
 }
 
+void AXLayoutObject::getRelativeBounds(AXObject** outContainer, FloatRect& outBoundsInContainer, SkMatrix44& outContainerTransform) const
+{
+    *outContainer = nullptr;
+    outBoundsInContainer = FloatRect();
+    outContainerTransform.setIdentity();
+
+    if (!m_layoutObject)
+        return;
+
+    // First compute the container. The container must be an ancestor in the accessibility tree, and
+    // its LayoutObject must be an ancestor in the layout tree. Get the first such ancestor that's
+    // either scrollable or has a paint layer.
+    AXObject* container = parentObjectUnignored();
+    LayoutObject* containerLayoutObject = nullptr;
+    while (container) {
+        containerLayoutObject = container->getLayoutObject();
+        if (containerLayoutObject && containerLayoutObject->isBoxModelObject() && m_layoutObject->isDescendantOf(containerLayoutObject)) {
+            if (container->isScrollableContainer() || containerLayoutObject->hasLayer())
+                break;
+        }
+
+        container = container->parentObjectUnignored();
+    }
+
+    if (!container)
+        return;
+    *outContainer = container;
+
+    // Next get the local bounds of this LayoutObject, which is typically
+    // a rect at point (0, 0) with the width and height of the LayoutObject.
+    LayoutRect localBounds;
+    if (m_layoutObject->isText()) {
+        localBounds = toLayoutText(m_layoutObject)->linesBoundingBox();
+    } else if (m_layoutObject->isLayoutInline()) {
+        localBounds = toLayoutInline(m_layoutObject)->linesBoundingBox();
+    } else if (m_layoutObject->isBox()) {
+        localBounds = LayoutRect(LayoutPoint(), toLayoutBox(m_layoutObject)->size());
+    } else if (m_layoutObject->isSVG()) {
+        localBounds = LayoutRect(m_layoutObject->strokeBoundingBox());
+    } else {
+        DCHECK(false);
+    }
+    outBoundsInContainer = FloatRect(localBounds);
+
+    // If the container has a scroll offset, subtract that out because we want our
+    // bounds to be relative to the *unscrolled* position of the container object.
+    ScrollableArea* scrollableArea = container->getScrollableAreaIfScrollable();
+    if (scrollableArea) {
+        IntPoint scrollPosition = scrollableArea->scrollPosition();
+        outBoundsInContainer.move(FloatSize(scrollPosition.x(), scrollPosition.y()));
+    }
+
+    // Compute the transform between the container's coordinate space and this object.
+    // If the transform is just a simple translation, apply that to the bounding box, but
+    // if it's a non-trivial transformation like a rotation, scaling, etc. then return
+    // the full matrix instead.
+    TransformationMatrix transform = m_layoutObject->localToAncestorTransform(toLayoutBoxModelObject(containerLayoutObject));
+    if (transform.isIdentityOr2DTranslation()) {
+        outBoundsInContainer.move(transform.to2DTranslation());
+    } else {
+        outContainerTransform = TransformationMatrix::toSkMatrix44(transform);
+    }
+}
+
 static bool isImageOrAltText(LayoutBoxModelObject* box, Node* node)
 {
     if (box && box->isImage())
         return true;
     if (isHTMLImageElement(node))
         return true;
     if (isHTMLInputElement(node) && toHTMLInputElement(node)->hasFallbackContent())
         return true;
     return false;
 }
@@ skipping 2233 matching lines @@
                     result.unite(labelRect);
                 }
             }
         }
     }
 
     return result;
 }
 
 } // namespace blink