Bug 722248 - Some chrome accessibles report incorrect visibility states. r=MarcoZ

Timothy wants us to stop using views, so we'll use frame API instead.
This is a pseudo-revert of some of bug 591363.

accessible/src/base/nsAccessible.cpp

@@ -593,30 +593,13 @@ nsAccessible::VisibilityState()
 {
   PRUint64 vstates = states::INVISIBLE | states::OFFSCREEN;
 
-  // We need to check the parent chain for visibility.
-  nsAccessible* accessible = this;
-  do {
-    // We don't want background tab page content to be aggressively invisible.
-    // Otherwise this foils screen reader virtual buffer caches.
-    roles::Role role = accessible->Role();
-    if (role == roles::PROPERTYPAGE || role == roles::PANE)
-      break;
-
-    nsIFrame* frame = accessible->GetFrame();
-    if (!frame)
-      return vstates;
-
-    const nsIView* view = frame->GetView();
-    if (view && view->GetVisibility() == nsViewVisibility_kHide)
-      return vstates;
-    
-  } while (accessible = accessible->Parent());
-
   nsIFrame* frame = GetFrame();
   if (!frame)
     return vstates;
 
   const nsCOMPtr<nsIPresShell> shell(GetPresShell());
+  if (!shell)
+    return vstates;
 
   // We need to know if at least a kMinPixels around the object is visible,
   // otherwise it will be marked states::OFFSCREEN.
@@ -644,6 +627,10 @@ nsAccessible::VisibilityState()
 
   }
 
+  // XXX Do we really need to cross from content to chrome ancestor?
+  if (!frame->IsVisibleConsideringAncestors(nsIFrame::VISIBILITY_CROSS_CHROME_CONTENT_BOUNDARY))
+    return vstates;
+
   // Assume we are visible enough.
   return vstates &= ~states::INVISIBLE;
 }