# HG changeset patch
# User Emilio Cobos Alvarez <emilio@crisal.io>
# Date 1524786410 -7200
# Node ID a42293258ab3dffb794f3a1e8fe2c3937dd81bb5
# Parent  18e58f90f23b4ee1d14078787e2409bd80eba945
Bug 1425866: Just null-check the CSS Loader for now. r=heycam

After discussing with Olli there isn't any kind of severe problem out of this.
Shadow subtrees will be disconnected just like the rest, and they shouldn't
assume that the document hasn't been disconnected first.

MozReview-Commit-ID: CX4fXOqEIFj

diff --git a/dom/base/nsStyleLinkElement.cpp b/dom/base/nsStyleLinkElement.cpp
--- a/dom/base/nsStyleLinkElement.cpp
+++ b/dom/base/nsStyleLinkElement.cpp
@@ -254,17 +254,18 @@ nsStyleLinkElement::DoUpdateStyleSheet(n
   // When static documents are created, stylesheets are cloned manually.
   if (mDontLoadStyle || !mUpdatesEnabled ||
       thisContent->OwnerDoc()->IsStaticDocument()) {
     return Update { };
   }
 
   nsCOMPtr<nsIDocument> doc = thisContent->IsInShadowTree() ?
     thisContent->OwnerDoc() : thisContent->GetUncomposedDoc();
-  if (!doc || !doc->CSSLoader()->GetEnabled()) {
+  // Loader could be null during unlink, see bug 1425866.
+  if (!doc || !doc->CSSLoader() || !doc->CSSLoader()->GetEnabled()) {
     return Update { };
   }
 
   bool isInline;
   nsCOMPtr<nsIPrincipal> triggeringPrincipal;
   nsCOMPtr<nsIURI> uri = GetStyleSheetURL(&isInline, getter_AddRefs(triggeringPrincipal));
   if (aForceUpdate == ForceUpdate::No && mStyleSheet && !isInline && uri) {
     if (nsIURI* oldURI = mStyleSheet->GetSheetURI()) {