Bug 380716, Crash [@ nsContentUtils::ContentIsDescendantOf], r+sr=jst

content/base/src/nsGenericElement.cpp

@@ -1904,7 +1904,9 @@ nsGenericElement::doPreHandleEvent(nsIContent* aContent,
           (aVisitor.mEvent->originalTarget == aContent &&
            (aVisitor.mRelatedTargetIsInAnon = IsInAnonContent(relatedTarget)))) {
         nsIContent* nonAnon = FindFirstNonAnonContent(aContent);
+        if (nonAnon) {
           nsIContent* nonAnonRelated = FindFirstNonAnonContent(relatedTarget);
+          if (nonAnonRelated) {
             if (nonAnon == nonAnonRelated ||
                 nsContentUtils::ContentIsDescendantOf(nonAnonRelated, nonAnon)) {
               aVisitor.mParentTarget = nsnull;
@@ -1915,6 +1917,8 @@ nsGenericElement::doPreHandleEvent(nsIContent* aContent,
           }
         }
       }
+    }
+  }
 
   nsCOMPtr<nsIContent> parent = aContent->GetParent();
   if (isAnonForEvents) {