Update the accessibility tree when a modal dialog is opened/closed.

Source/core/html/HTMLDialogElement.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
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/html/HTMLDialogElement.h"
 
 #include "bindings/v8/ExceptionState.h"
+#include "core/accessibility/AXObjectCache.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/html/HTMLFormControlElement.h"
 #include "core/frame/FrameView.h"
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/style/RenderStyle.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
@@ skipping 10 matching lines @@
                 return;
             }
         }
         if (node->hasTagName(dialogTag))
             next = NodeTraversal::nextSkippingChildren(node, dialog);
         else
             next = NodeTraversal::next(node, dialog);
     }
 }
 
+static void inertSubtreesChanged(Document& document)
+{
+    if (AXObjectCache* cache = document.existingAXObjectCache())
+        cache->updateCacheAfterInertSubtreesChanged();
+}
+
 HTMLDialogElement::HTMLDialogElement(const QualifiedName& tagName, Document& document)
     : HTMLElement(tagName, document)
     , m_centeringMode(Uninitialized)
     , m_centeredPosition(0)
     , m_returnValue("")
 {
     ASSERT(hasTagName(dialogTag));
     ScriptWrappable::init(this);
 }
 
 PassRefPtr<HTMLDialogElement> HTMLDialogElement::create(const QualifiedName& tagName, Document& document)
 {
     return adoptRef(new HTMLDialogElement(tagName, document));
 }
 
 void HTMLDialogElement::close(const String& returnValue, ExceptionState& es)
 {
     if (!fastHasAttribute(openAttr)) {
         es.throwUninformativeAndGenericDOMException(InvalidStateError);
         return;
     }
     closeDialog(returnValue);
 }
 
 void HTMLDialogElement::closeDialog(const String& returnValue)
 {
     if (!fastHasAttribute(openAttr))
         return;
     setBooleanAttribute(openAttr, false);
+
+    HTMLDialogElement* activeModalDialog = document().activeModalDialog();
     document().removeFromTopLayer(this);
+    if (activeModalDialog == this)
+        inertSubtreesChanged(document());
 
     if (!returnValue.isNull())
         m_returnValue = returnValue;
 
     dispatchScopedEvent(Event::create(EventTypeNames::close));
 }
 
 void HTMLDialogElement::forceLayoutForCentering()
 {
     m_centeringMode = Uninitialized;
@@ skipping 10 matching lines @@
     forceLayoutForCentering();
 }
 
 void HTMLDialogElement::showModal(ExceptionState& es)
 {
     if (fastHasAttribute(openAttr) || !inDocument()) {
         es.throwUninformativeAndGenericDOMException(InvalidStateError);
         return;
     }
     document().addToTopLayer(this);
+    inertSubtreesChanged(document());

[dmazzoni, 2013/11/07 16:35:59]

Might be nice to do this at the end - after setting "open" to true and after
layout, since those may cause AX events too. In particular, layout will clear
the cache and it'd be a waste to clear the cache immediately after touching the
whole tree.

[falken, 2013/11/07 23:54:58]

Yeah I actually had tried that but somehow the AX tree wasn't updated correctly
for http://demo.agektmr.com/dialog/, which suggests there may be a bug with the
updating logic. I'll try to track that down, maybe in a separate patch.

     setBooleanAttribute(openAttr, true);
 
     runAutofocus(this);
     forceLayoutForCentering();
 }
 
 void HTMLDialogElement::setCentered(LayoutUnit centeredPosition)
 {
     ASSERT(m_centeringMode == Uninitialized);
     m_centeredPosition = centeredPosition;
@@ skipping 27 matching lines @@
 }
 
 bool HTMLDialogElement::shouldBeReparentedUnderRenderView(const RenderStyle* style) const
 {
     if (style && style->position() == AbsolutePosition)
         return true;
     return Element::shouldBeReparentedUnderRenderView(style);
 }
 
 } // namespace WebCore