--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -437,26 +437,28 @@ nsComputedDOMStyle::GetStyleContextForEl
 {
   MOZ_ASSERT(aElement, "NULL element");
   // If the content has a pres shell, we must use it.  Otherwise we'd
   // potentially mix rule trees by using the wrong pres shell's style
   // set.  Using the pres shell from the content also means that any
   // content that's actually *in* a document will get the style from the
   // correct document.
   nsIPresShell *presShell = GetPresShellForContent(aElement);
+  bool inDocWithShell = true;
   if (!presShell) {
+    inDocWithShell = false;
     presShell = aPresShell;
     if (!presShell)
       return nullptr;
   }
 
   // XXX the !aElement->IsHTMLElement(nsGkAtoms::area)
   // check is needed due to bug 135040 (to avoid using
   // mPrimaryFrame). Remove it once that's fixed.
-  if (!aPseudo && aStyleType == eAll &&
+  if (!aPseudo && aStyleType == eAll && inDocWithShell &&
       !aElement->IsHTMLElement(nsGkAtoms::area)) {
     nsIFrame* frame = nsLayoutUtils::GetStyleFrame(aElement);
     if (frame) {
       nsStyleContext* result = frame->StyleContext();
       // Don't use the style context if it was influenced by
       // pseudo-elements, since then it's not the primary style
       // for this element.
       if (!result->HasPseudoElementData()) {
@@ -485,17 +487,18 @@ nsComputedDOMStyle::GetStyleContextForEl
 
   RefPtr<nsStyleContext> sc;
   if (aPseudo) {
     nsCSSPseudoElements::Type type = nsCSSPseudoElements::GetPseudoType(aPseudo);
     if (type >= nsCSSPseudoElements::ePseudo_PseudoElementCount) {
       return nullptr;
     }
     nsIFrame* frame = nsLayoutUtils::GetStyleFrame(aElement);
-    Element* pseudoElement = frame ? frame->GetPseudoElement(type) : nullptr;
+    Element* pseudoElement =
+      frame && inDocWithShell ? frame->GetPseudoElement(type) : nullptr;
     sc = styleSet->ResolvePseudoElementStyle(aElement, type, parentContext,
                                              pseudoElement);
   } else {
     sc = styleSet->ResolveStyleFor(aElement, parentContext);
   }
 
   if (aStyleType == eDefaultOnly) {
     // We really only want the user and UA rules.  Filter out the other ones.