From c32c0ac9dc62f86493ea8fa98217d92f53cdca70 Mon Sep 17 00:00:00 2001
From: "J. Ryan Stinnett" <jryans@gmail.com>
Date: Thu, 22 Jun 2017 17:48:04 -0500
Subject: [PATCH] Drop root_flow to avoid rule node leaks

---
 components/layout_thread/lib.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
index ce3a7e28b7d..96eac55cc5b 100644
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@@ -793,6 +793,10 @@ impl LayoutThread {
     /// Shuts down the layout thread now. If there are any DOM nodes left, layout will now (safely)
     /// crash.
     fn exit_now(&mut self) {
+        // Drop the root flow explicitly to avoid holding style data, such as
+        // rule nodes.  The `Stylist` checks when it is dropped that all rule
+        // nodes have been GCed, so we want drop anyone who holds them first.
+        self.root_flow.borrow_mut().take();
         // Drop the rayon threadpool if present.
         let _ = self.parallel_traversal.take();
     }