Implement aria properties setsize and posinset.

Source/modules/accessibility/AXNodeObject.cpp

 /*
 * Copyright (C) 2012, Google 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 1154 matching lines @@
         WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement>>
             invalidControls;
         bool isInvalid = !element->checkValidity(
             &invalidControls, CheckValidityDispatchNoEvent);
         return isInvalid ? InvalidStateTrue : InvalidStateFalse;
     }
 
     return InvalidStateUndefined;
 }
 
+int AXNodeObject::posInSet() const
+{
+    if (supportsSetSizeAndPosInSet()) {
+        if (hasAttribute(aria_posinsetAttr))
+            return getAttribute(aria_posinsetAttr).toInt();
+        return node()->nodeIndex();

[dmazzoni, 2015/04/10 17:35:21]

Do a null check here.

(The reason this can be null is that AXObjects are reference-counted, so when an
HTML element is destroyed, we get a callback and "detach" the AXObject from its
node (and similarly from layoutObject). The AXObject gets deleted pretty soon
usually, but it's possible that it still exists for a short period of time when
detached so we always need to check if node() and layoutObject() are null.)

+    }
+
+    return 0;
+}
+
+int AXNodeObject::setSize() const
+{
+    if (supportsSetSizeAndPosInSet()) {
+        if (hasAttribute(aria_setsizeAttr))
+            return getAttribute(aria_setsizeAttr).toInt();
+        if (node()->parentNode())
+            return node()->parentNode()->countChildren();

[dmazzoni, 2015/04/10 17:35:21]

I just realized that this isn't going to do the right thing for:

<select>
  <optgroup>
    <option>1</option>
    <option>2</option>
  </optgroup>
  <optgroup>
    <option>3</option>
    <option>4</option>
  </optgroup>
</select>

In this case the DOM tree is more complicated, but the AX tree will be simpler,
it will look more like:

AXMenuListPopup
  AXMenuListOption
  AXMenuListOption
  AXMenuListOption
  AXMenuListOption

or:

AXListBox
  AXListBoxOption
  AXListBoxOption
  AXListBoxOption
  AXListBoxOption

So I think it'd be best to count the children of the AXObject's parent object.

Similarly for posInSet, above - that may mean implementing our own indexInParent
function if it doesn't exist yet.

[shreeramk, 2015/04/13 03:49:59]

Yes it doesn't exist currently.

From blink we can return the attr values of aria_posinset & aria_setsize if
those are present else in chromium side we can call indexinparent and
platformchildcount api to get the required values. Will that not be a good
option?

+    }
+
+    return 0;
+}
+
 String AXNodeObject::ariaInvalidValue() const
 {
     if (invalidState() == InvalidStateOther)
         return getAttribute(aria_invalidAttr);
 
     return String();
 }
 
 String AXNodeObject::valueDescription() const
 {
@@ skipping 897 matching lines @@
     float range = maxValueForRange() - minValueForRange();
     float value = valueForRange();
 
     value += range * (percentChange / 100);
     setValue(String::number(value));
 
     axObjectCache()->postNotification(node(), AXObjectCacheImpl::AXValueChanged);
 }
 
 } // namespace blink