Bug 1423990 - Follow-up for conditionally compiled code for Thunderbird. r=smaug

--HG--
extra : amend_source : e1e50e7e55d2c014b2ae8487f2cf9b7299da5879

dom/base/nsDocumentEncoder.cpp

@@ -1409,7 +1409,8 @@ nsHTMLCopyEncoder::SetSelection(nsISelection* aSelection)
       // Wait for Firefox to get fixed to detect pre-formatting correctly,
       // bug 1174452.
       nsAutoString styleVal;
-      if (selContent->GetAttr(kNameSpaceID_None, nsGkAtoms::style, styleVal) &&
+      if (selContent->IsElement() &&
+          selContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::style, styleVal) &&
           styleVal.Find(NS_LITERAL_STRING("pre-wrap")) != kNotFound) {
         mIsTextWidget = true;
         break;