Bug 1340885 - Null check frame's content when searching for NAC ancestors in GetCorrectedParent. r=xidorn

MozReview-Commit-ID: 7u2yKe8ir1V

--HG--
extra : rebase_source : 27bef0319b3d3744f29f53af51536c4c350bf8e8

layout/generic/nsFrame.cpp

@@ -9105,7 +9105,8 @@ GetCorrectedParent(const nsIFrame* aFrame)
   // box, or a non-NAC-backed pseudo like ::first-line) that does not match the
   // one that the NAC implements, if any.
   nsIContent* content = aFrame->GetContent();
-  Element* element = content->IsElement() ? content->AsElement() : nullptr;
+  Element* element =
+    content && content->IsElement() ? content->AsElement() : nullptr;
   if (element && element->IsNativeAnonymous() &&
       element->GetPseudoElementType() == aFrame->StyleContext()->GetPseudoType()) {
     while (parent->GetContent() && parent->GetContent()->IsNativeAnonymous()) {