Expose scroll containers via accessibility APIs.

Source/modules/accessibility/AXObject.cpp

 /*
  * Copyright (C) 2008, 2009, 2011 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 990 matching lines @@
     if (!elementNode)
         return nullAtom;
 
     if (!elementNode->isElementNode())
         return nullAtom;
 
     Element* element = toElement(elementNode);
     return element->fastGetAttribute(attribute);
 }
 
+//
+// Scrollable containers.
+//
+
+//
+// Scrollable containers.

[aboxhall, 2015/05/01 23:05:42]

Double comment?

+//
+
+bool AXObject::isScrollableContainer() const
+{
+    return !!getScrollableAreaIfScrollable();

[aboxhall, 2015/05/01 23:05:42]

Ugh, I don't like !! but it seems to be the de facto standard in blink code.

+}
+
+IntPoint AXObject::scrollOffset() const
+{
+    ScrollableArea* area = getScrollableAreaIfScrollable();
+    if (!area)
+        return IntPoint();
+
+    return IntPoint(area->scrollPosition().x(), area->scrollPosition().y());
+}
+
+IntPoint AXObject::minimumScrollOffset() const
+{
+    ScrollableArea* area = getScrollableAreaIfScrollable();
+    if (!area)
+        return IntPoint();
+
+    return IntPoint(area->minimumScrollPosition().x(), area->minimumScrollPosition().y());
+}
+
+IntPoint AXObject::maximumScrollOffset() const
+{
+    ScrollableArea* area = getScrollableAreaIfScrollable();
+    if (!area)
+        return IntPoint();
+
+    return IntPoint(area->maximumScrollPosition().x(), area->maximumScrollPosition().y());
+}
+
+void AXObject::setScrollOffset(const IntPoint& offset) const
+{
+    ScrollableArea* area = getScrollableAreaIfScrollable();
+    if (!area)
+        return;
+
+    area->setScrollPosition(DoublePoint(offset.x(), offset.y()));
+}
+
+//
+// Modify or take an action on an object.
+//
+
 bool AXObject::press() const
 {
     Element* actionElem = actionElement();
     if (!actionElem)
         return false;
     UserGestureIndicator gestureIndicator(DefinitelyProcessingNewUserGesture);
     actionElem->accessKeyAction(true);
     return true;
 }
 
@@ skipping 117 matching lines @@
         scrollPosition.x(),
         objectRect.x() + subfocus.x(), objectRect.x() + subfocus.maxX(),
         objectRect.x(), objectRect.maxX(),
         0, scrollVisibleRect.width());
     int desiredY = computeBestScrollOffset(
         scrollPosition.y(),
         objectRect.y() + subfocus.y(), objectRect.y() + subfocus.maxY(),
         objectRect.y(), objectRect.maxY(),
         0, scrollVisibleRect.height());
 
-    scrollParent->scrollTo(IntPoint(desiredX, desiredY));
+    scrollParent->setScrollOffset(IntPoint(desiredX, desiredY));
 
     // Convert the subfocus into the coordinates of the scroll parent.
     IntRect newSubfocus = subfocus;
     IntRect newElementRect = pixelSnappedIntRect(elementRect());
     IntRect scrollParentRect = pixelSnappedIntRect(scrollParent->elementRect());
     newSubfocus.move(newElementRect.x(), newElementRect.y());
     newSubfocus.move(-scrollParentRect.x(), -scrollParentRect.y());
 
     // Recursively make sure the scroll parent itself is visible.
     if (scrollParent->parentObject())
@@ skipping 35 matching lines @@
         int desiredX = computeBestScrollOffset(
             0,
             objectRect.x(), objectRect.maxX(),
             objectRect.x(), objectRect.maxX(),
             point.x(), point.x());
         int desiredY = computeBestScrollOffset(
             0,
             objectRect.y(), objectRect.maxY(),
             objectRect.y(), objectRect.maxY(),
             point.y(), point.y());
-        outer->scrollTo(IntPoint(desiredX, desiredY));
+        outer->setScrollOffset(IntPoint(desiredX, desiredY));
 
         if (outer->isAXScrollView() && !inner->isAXScrollView()) {
             // If outer object we just scrolled is a scroll view (main window or iframe) but the
             // inner object is not, keep track of the coordinate transformation to apply to
             // future nested calculations.
             scrollPosition = scrollableArea->scrollPosition();
             offsetX -= (scrollPosition.x() + point.x());
             offsetY -= (scrollPosition.y() + point.y());
             point.move(scrollPosition.x() - innerRect.x(), scrollPosition.y() - innerRect.y());
         } else if (inner->isAXScrollView()) {
@@ skipping 140 matching lines @@
 }
 
 const AtomicString& AXObject::internalRoleName(AccessibilityRole role)
 {
     static const Vector<AtomicString>* internalRoleNameVector = createInternalRoleNameVector();
 
     return internalRoleNameVector->at(role);
 }
 
 } // namespace blink