From e7449d541fbcd71e99455861e5e29c0724e5782a Mon Sep 17 00:00:00 2001
From: Paul Rouget <me@paulrouget.com>
Date: Tue, 8 Dec 2015 11:00:57 +0100
Subject: [PATCH] Freeze old pipeline in iframes

---
 components/compositing/constellation.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/components/compositing/constellation.rs b/components/compositing/constellation.rs
index c876e6e7a4d..131dfbd9e1d 100644
--- a/components/compositing/constellation.rs
+++ b/components/compositing/constellation.rs
@@ -834,6 +834,10 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
             }
         };
 
+        if let Some(pipeline_id) = old_pipeline_id {
+            self.pipeline(pipeline_id).freeze();
+        }
+
         // Create the new pipeline, attached to the parent and push to pending frames
         let window_size = old_pipeline_id.and_then(|old_pipeline_id| {
             self.pipeline(old_pipeline_id).size