Bug 246236. Accessible trees need to be invalidated when mView changes. r=ginn.chen, sr=neil

accessible/src/base/nsRootAccessible.cpp

@@ -228,6 +228,8 @@ const char* const docEvents[] = {
   "ValueChange",
   // capture AlertActive events (fired whenever alert pops up)
   "AlertActive",
+  // add ourself as a TreeViewChanged listener (custom event fired in nsTreeBodyFrame.cpp)
+  "TreeViewChanged",
   // add ourself as a OpenStateChange listener (custom event fired in tree.xml)
   "OpenStateChange",
   // add ourself as a CheckboxStateChange listener (custom event fired in nsHTMLInputElement.cpp)
@@ -566,6 +568,13 @@ NS_IMETHODIMP nsRootAccessible::HandleEvent(nsIDOMEvent* aEvent)
     return NS_OK;
   }
 
+  if (eventType.EqualsLiteral("TreeViewChanged")) {
+    NS_ENSURE_TRUE(localName.EqualsLiteral("tree"), NS_OK);
+    nsCOMPtr<nsIContent> treeContent = do_QueryInterface(targetNode);
+    return mAccService->InvalidateSubtreeFor(eventShell, treeContent,
+                                             nsIAccessibleEvent::EVENT_REORDER);
+  }
+
   nsCOMPtr<nsIAccessible> accessible;
   if (NS_FAILED(mAccService->GetAccessibleInShell(targetNode, eventShell,
                                                   getter_AddRefs(accessible))))

accessible/src/xul/nsXULTreeAccessible.cpp

@@ -394,7 +394,10 @@ NS_IMETHODIMP nsXULTreeAccessible::GetCachedTreeitemAccessible(PRInt32 aRow, nsI
   NS_ASSERTION(mAccessNodeCache, "No accessibility cache for tree");
   NS_ASSERTION(mTree && mTreeView, "Can't get mTree or mTreeView!\n");
 
-  nsCOMPtr<nsITreeColumn> col = aColumn;
+  nsCOMPtr<nsITreeColumn> col;
+#ifdef MOZ_ACCESSIBILITY_ATK
+  col = aColumn;
+#endif
   PRInt32 columnIndex = -1;
 
   if (!col && mTree) {

layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp

@@ -517,6 +517,11 @@ NS_IMETHODIMP nsTreeBodyFrame::SetView(nsITreeView * aView)
   // necessarily entail a full invalidation of the tree.
   Invalidate();
  
+  nsIContent *treeContent = GetBaseElement();
+  if (treeContent) {
+    FireDOMEvent(NS_LITERAL_STRING("TreeViewChanged"), treeContent);
+  }
+
   if (mView) {
     // Give the view a new empty selection object to play with, but only if it
     // doesn't have one already.