Bug 1475708 - Block setting cookies using document.cookie when restricting 3rd party storage; r=baku

dom/html/nsHTMLDocument.cpp

@@ -1162,6 +1162,11 @@ nsHTMLDocument::SetCookie(const nsAString& aCookie, ErrorResult& rv)
     return;
   }
 
+  if (nsContentUtils::StorageDisabledByAntiTracking(GetInnerWindow(), nullptr,
+                                                    nullptr)) {
+    return;
+  }
+
   // If the document is a cookie-averse Document... do nothing.
   if (IsCookieAverse()) {
     return;

toolkit/components/antitracking/test/browser/browser_blockingCookies.js

@@ -4,6 +4,8 @@ AntiTracking.runTest("Set/Get Cookies",
   // Blocking callback
   async _ => {
     is(document.cookie, "", "No cookies for me");
+    document.cookie = "name=value";
+    is(document.cookie, "", "No cookies for me");
 
     await fetch("server.sjs").then(r => r.text()).then(text => {
       is(text, "cookie-not-present", "We should not have cookies");
@@ -23,6 +25,11 @@ AntiTracking.runTest("Set/Get Cookies",
     await fetch("server.sjs").then(r => r.text()).then(text => {
       is(text, "cookie-not-present", "We should not have cookies");
     });
+
+    document.cookie = "name=value";
+    ok(document.cookie.includes("name=value"), "Some cookies for me");
+    ok(document.cookie.includes("foopy=1"), "Some cookies for me");
+
     await fetch("server.sjs").then(r => r.text()).then(text => {
       is(text, "cookie-present", "We should have cookies");
     });