diff --git a/toolkit/components/extensions/test/mochitest/test_ext_activityLog.html b/toolkit/components/extensions/test/mochitest/test_ext_activityLog.html
index 48f8b815cfc6..408b750ef5f4 100644
--- a/toolkit/components/extensions/test/mochitest/test_ext_activityLog.html
+++ b/toolkit/components/extensions/test/mochitest/test_ext_activityLog.html
@@ -193,6 +193,8 @@ add_task(async function test_api() {
               thirdParty: false,
               ip: null,
               frameAncestors: [],
+              requestSize: 0,
+              responseSize: 0,
               incognito: false,
             },
           ],
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_webRequest_requestSize.js b/toolkit/components/extensions/test/xpcshell/test_ext_webRequest_requestSize.js
index 4c271fc8629c..0a4f47f5436c 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_webRequest_requestSize.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_webRequest_requestSize.js
@@ -13,8 +13,6 @@ const EXTENSION_DATA = {
     permissions: ["webRequest", "<all_urls>"],
   },
 
-  isPrivileged: true,
-
   async background() {
     browser.test.log("background script running");
 
diff --git a/toolkit/components/extensions/webrequest/WebRequest.jsm b/toolkit/components/extensions/webrequest/WebRequest.jsm
index b32c95f1f1aa..79cbf3430f70 100644
--- a/toolkit/components/extensions/webrequest/WebRequest.jsm
+++ b/toolkit/components/extensions/webrequest/WebRequest.jsm
@@ -786,6 +786,8 @@ HttpObserverManager = {
       proxyInfo: channel.proxyInfo,
 
       serialize: serializeRequestData,
+      requestSize: channel.requestSize,
+      responseSize: channel.responseSize,
     };
 
     return Object.assign(data, extraData);
@@ -856,8 +858,6 @@ HttpObserverManager = {
         let { policy } = opts;
         if (policy && policy.extension.isPrivileged) {
           data.urlClassification = channel.urlClassification;
-          data.requestSize = channel.requestSize;
-          data.responseSize = channel.responseSize;
         }
 
         if (registerFilter && opts.blocking && opts.policy) {