diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index a701b14141b6..ddc13df268e2 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -2712,6 +2712,27 @@ NS_IsOffline()
     return offline || !connectivity;
 }
 
+nsresult
+NS_NotifyCurrentTopLevelOuterContentWindowId(uint64_t aWindowId)
+{
+  nsCOMPtr<nsIObserverService> obs =
+    do_GetService("@mozilla.org/observer-service;1");
+  if (!obs) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsISupportsPRUint64> wrapper =
+    do_CreateInstance(NS_SUPPORTS_PRUINT64_CONTRACTID);
+  if (!wrapper) {
+    return NS_ERROR_FAILURE;
+  }
+
+  wrapper->SetData(aWindowId);
+  return obs->NotifyObservers(wrapper,
+                              "net:current-toplevel-outer-content-windowid",
+                              nullptr);
+}
+
 namespace mozilla {
 namespace net {
 
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index d7d54b6d9d08..9c562debf36e 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -943,6 +943,11 @@ nsresult NS_CompareLoadInfoAndLoadContext(nsIChannel *aChannel);
  */
 uint32_t NS_GetDefaultReferrerPolicy();
 
+/**
+ * Update the window id of the current focused top level content window.
+ */
+nsresult NS_NotifyCurrentTopLevelOuterContentWindowId(uint64_t aWindowId);
+
 namespace mozilla {
 namespace net {
 
diff --git a/netwerk/ipc/NeckoParent.cpp b/netwerk/ipc/NeckoParent.cpp
index de1596d9405e..b9aabe3fd05e 100644
--- a/netwerk/ipc/NeckoParent.cpp
+++ b/netwerk/ipc/NeckoParent.cpp
@@ -45,6 +45,7 @@
 #include "nsINetworkPredictorVerifier.h"
 #include "nsISpeculativeConnect.h"
 #include "nsIThrottlingService.h"
+#include "nsNetUtil.h"
 
 using mozilla::OriginAttributes;
 using mozilla::dom::ChromeUtils;
@@ -914,5 +915,15 @@ NeckoParent::RecvDecreaseThrottlePressure()
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult
+NeckoParent::RecvNotifyCurrentTopLevelOuterContentWindowId(const uint64_t& aWindowId)
+{
+  if (NS_FAILED(NS_NotifyCurrentTopLevelOuterContentWindowId(aWindowId))) {
+    NS_WARNING("NS_NotifyCurrentTopLevelOuterContentWindowId failed!");
+  }
+
+  return IPC_OK();
+}
+
 } // namespace net
 } // namespace mozilla
diff --git a/netwerk/ipc/NeckoParent.h b/netwerk/ipc/NeckoParent.h
index c3dd6ce2a24d..75df81d9e0cc 100644
--- a/netwerk/ipc/NeckoParent.h
+++ b/netwerk/ipc/NeckoParent.h
@@ -229,6 +229,8 @@ protected:
   virtual mozilla::ipc::IPCResult RecvIncreaseThrottlePressure() override;
   virtual mozilla::ipc::IPCResult RecvDecreaseThrottlePressure() override;
 
+  virtual mozilla::ipc::IPCResult
+  RecvNotifyCurrentTopLevelOuterContentWindowId(const uint64_t& aWindowId) override;
 private:
   nsTArray<mozilla::UniquePtr<mozilla::net::Throttler>> mThrottlers;
 };
diff --git a/netwerk/ipc/PNecko.ipdl b/netwerk/ipc/PNecko.ipdl
index 830842aae2de..4583febf598b 100644
--- a/netwerk/ipc/PNecko.ipdl
+++ b/netwerk/ipc/PNecko.ipdl
@@ -123,6 +123,8 @@ parent:
   async IncreaseThrottlePressure();
   async DecreaseThrottlePressure();
 
+  prio(high) async NotifyCurrentTopLevelOuterContentWindowId(uint64_t windowId);
+
 child:
   /*
    * Bring up the http auth prompt for a nested remote mozbrowser.
diff --git a/netwerk/protocol/http/nsHttpHandler.cpp b/netwerk/protocol/http/nsHttpHandler.cpp
index f833109483fa..9f9116da3aa7 100644
--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -53,6 +53,7 @@
 #include "nsIOService.h"
 #include "nsIUUIDGenerator.h"
 #include "nsIThrottlingService.h"
+#include "nsISupportsPrimitives.h"
 
 #include "mozilla/net/NeckoChild.h"
 #include "mozilla/net/NeckoParent.h"
@@ -385,6 +386,9 @@ nsHttpHandler::Init()
         obsService->AddObserver(this, "browser:purge-session-history", true);
         obsService->AddObserver(this, NS_NETWORK_LINK_TOPIC, true);
         obsService->AddObserver(this, "application-background", true);
+        obsService->AddObserver(this,
+                                "net:current-toplevel-outer-content-windowid",
+                                true);
 
         // disabled as its a nop right now
         // obsService->AddObserver(this, "net:failed-to-process-uri-content", true);
@@ -2126,6 +2130,29 @@ nsHttpHandler::Observe(nsISupports *subject,
                      static_cast<uint32_t>(rv)));
             }
         }
+    } else if (!strcmp(topic, "net:current-toplevel-outer-content-windowid")) {
+        nsCOMPtr<nsISupportsPRUint64> wrapper = do_QueryInterface(subject);
+        MOZ_RELEASE_ASSERT(wrapper);
+
+        uint64_t windowId = 0;
+        wrapper->GetData(&windowId);
+        MOZ_ASSERT(windowId);
+
+        if (IsNeckoChild()) {
+            if (gNeckoChild) {
+                gNeckoChild->SendNotifyCurrentTopLevelOuterContentWindowId(
+                    windowId);
+            }
+        } else {
+            static uint64_t sCurrentTopLevelOuterContentWindowId = 0;
+            if (sCurrentTopLevelOuterContentWindowId != windowId) {
+                sCurrentTopLevelOuterContentWindowId = windowId;
+                if (mConnMgr) {
+                    mConnMgr->UpdateCurrentTopLevelOuterContentWindowId(
+                        sCurrentTopLevelOuterContentWindowId);
+                }
+            }
+        }
     }
 
     return NS_OK;