Bug 1608985 - [1.0] Veto redirect when loading is denied by the delegate. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D61703

--HG--
extra : moz-landing-system : lando

uriloader/base/nsDocLoader.cpp

@@ -1473,7 +1473,8 @@ NS_IMETHODIMP nsDocLoader::AsyncOnChannelRedirect(
           newURI, where, nsIWebNavigation::LOAD_FLAGS_IS_REDIRECT,
           /* triggering principal */ nullptr, &loadURIHandled);
       if (NS_SUCCEEDED(rv) && loadURIHandled) {
-        cb->OnRedirectVerifyCallback(NS_OK);
+        aOldChannel->Cancel(NS_ERROR_ABORT);
+        cb->OnRedirectVerifyCallback(NS_ERROR_ABORT);
         return NS_OK;
       }
     }