Bug 444644 - When an OBJECT_SHOW event is fired, its MSAA states are not properly set yet; r=MarcoZ, r=surkov

accessible/src/base/nsAccessible.cpp

@@ -1935,6 +1935,14 @@ nsAccessible::GetState(PRUint32 *aState, PRUint32 *aExtraState)
 {
   NS_ENSURE_ARG_POINTER(aState);
 
+  if (!IsDefunct()) {
+    // Flush layout so that all the frame construction, reflow, and styles are
+    // up-to-date since we rely on frames, and styles when calculating state.
+    // We don't flush the display because we don't care about painting.
+    nsCOMPtr<nsIPresShell> presShell = GetPresShell();
+    presShell->FlushPendingNotifications(Flush_Layout);
+  }
+
   nsresult rv = GetStateInternal(aState, aExtraState);
   NS_ENSURE_A11Y_SUCCESS(rv, rv);
 

accessible/src/base/nsDocAccessible.cpp

@@ -1584,8 +1584,17 @@ NS_IMETHODIMP nsDocAccessible::FlushPendingEvents()
   nsCOMPtr<nsIPresShell> presShell = GetPresShell();
   if (!presShell)
     length = 0; // The doc is now shut down, don't fire events in it anymore
-  else
+  else {
+    // Flush layout so that all the frame construction, reflow, and styles are
+    // up-to-date. This will ensure we can get frames for the related nodes, as
+    // well as get the most current information for calculating things like
+    // visibility. We don't flush the display because we don't care about
+    // painting. If no flush is necessary the method will simple return.
+    presShell->FlushPendingNotifications(Flush_Layout);
+
+    // filter events
     nsAccEvent::ApplyEventRules(mEventsToFire);
+  }
   
   for (PRUint32 index = 0; index < length; index ++) {
     nsCOMPtr<nsIAccessibleEvent> accessibleEvent(