1 files changed, 18 insertions, 0 deletions
diff --git a/netwerk/ipc/DocumentLoadListener.cpp b/netwerk/ipc/DocumentLoadListener.cpp
index 54c9a53e65..a6a7b21749 100644
--- a/netwerk/ipc/DocumentLoadListener.cpp
+++ b/netwerk/ipc/DocumentLoadListener.cpp
@@ -777,6 +777,24 @@ auto DocumentLoadListener::Open(nsDocShellLoadState* aLoadState,
     if (cos && aUrgentStart) {
       cos->AddClassFlags(nsIClassOfService::UrgentStart);
     }
+
+    // ClientChannelHelper below needs us to have finalized the principal for
+    // the channel because it will request that StoragePrincipalHelper mint us a
+    // principal that needs to match the same principal that a later call to
+    // StoragePrincipalHelper will mint when determining the right origin to
+    // look up the ServiceWorker.
+    //
+    // Because nsHttpChannel::AsyncOpen calls UpdateAntiTrackingInfoForChannel
+    // which potentially flips the third party bit/flag on the partition key on
+    // the cookie jar which impacts the principal that will be minted, it is
+    // essential that UpdateAntiTrackingInfoForChannel is called before
+    // AddClientChannelHelperInParent below.
+    //
+    // Because the call to UpdateAntiTrackingInfoForChannel is largely
+    // idempotent, we currently just make the call ourselves right now.  The one
+    // caveat is that the RFPRandomKey may be spuriously regenerated for
+    // top-level documents.
+    AntiTrackingUtils::UpdateAntiTrackingInfoForChannel(httpChannel);
   }
 
   // Setup a ClientChannelHelper to watch for redirects, and copy