--- a/dom/ipc/manifestMessages.js
+++ b/dom/ipc/manifestMessages.js
@@ -64,30 +64,21 @@ function fetchManifest() {
     }
     const elem = content.document.querySelector(manifestQuery);
     if (!elem || !elem.getAttribute('href')) {
       let msg = 'No manifest to fetch.';
       return reject(new Error(msg));
     }
     // Will throw on "about:blank" and possibly other invalid URIs.
     const manifestURL = new content.URL(elem.href, elem.baseURI);
-    const reqInit = {};
-    switch (elem.crossOrigin) {
-      case 'use-credentials':
-        reqInit.credentials = 'include';
-        reqInit.mode = 'cors';
-        break;
-      case 'anonymous':
-        reqInit.credentials = 'omit';
-        reqInit.mode = 'cors';
-        break;
-      default:
-        reqInit.credentials = 'same-origin';
-        reqInit.mode = 'no-cors';
-        break;
+    const reqInit = {
+      mode: 'cors'
+    };
+    if (elem.crossOrigin === 'use-credentials') {
+      reqInit.credentials = 'include';
     }
     const req = new content.Request(manifestURL, reqInit);
     req.setContext('manifest');
     content
       .fetch(req)
       .then(resp => processResponse(resp, content))
       .then(resolve)
       .catch(reject);

--- a/dom/manifest/test/browser_ManifestObtainer_obtain.js
+++ b/dom/manifest/test/browser_ManifestObtainer_obtain.js
@@ -39,28 +39,27 @@ const tests = [
     run(manifest) {
       Assert.strictEqual(manifest.name, 'pass-2', this.expected);
     },
     testData: `
       <link rel="foo bar manifest bar test" href='resource.sjs?body={"name":"pass-2"}'>
       <link rel="manifest" href='resource.sjs?body={"name":"fail"}'>
       <link rel="manifest foo bar test" href='resource.sjs?body={"name":"fail"}'>`
   }, {
-    expected: 'By default, manifest load cross-origin.',
+    expected: 'By default, manifest cannot load cross-origin.',
     get tabURL() {
       let query = [
         `body=<h1>${this.expected}</h1>`,
         'Content-Type=text/html; charset=utf-8',
       ];
       const URL = `${defaultURL}?${query.join('&')}`;
       return URL;
     },
-    run(manifest) {
-      // Waiting on https://bugzilla.mozilla.org/show_bug.cgi?id=1130924
-      todo_is(manifest.name, 'pass-3', this.expected);
+    run(err) {
+      Assert.strictEqual(err.name, 'TypeError', this.expected);
     },
     testData: `<link rel="manifest" href='${remoteURL}?body={"name":"pass-3"}'>`
   },
   // CORS Tests.
   {
     expected: 'CORS enabled, manifest must be fetched.',
     get tabURL() {
       let query = [