Bug 403266 - usechromesheets attribute does not work if there is no userContent.css in the profile. r=dbaron

layout/base/nsDocumentViewer.cpp

@@ -2158,7 +2158,7 @@ DocumentViewerImpl::CreateStyleSet(nsIDocument* aDocument,
           if (!uri) continue;
 
           cssLoader->LoadSheetSync(uri, getter_AddRefs(csssheet));
-          if (!sheet) continue;
+          if (!csssheet) continue;
 
           styleSet->PrependStyleSheet(nsStyleSet::eAgentSheet, csssheet);
           shouldOverride = PR_TRUE;