Bug 1554354. Fix new u2f tests on Android. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D32555

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

dom/u2f/tests/test_bind.html

@@ -14,10 +14,15 @@
         // failure!  Run the actual code we want off something that will report
         // errors properly.
         SimpleTest.executeSoon(function() {
-            is(typeof(u2f.register.bind(u2f)), "function",
+            // Need a new global for the pref to really take effect.
+            var iframe = document.createElement("iframe");
+            document.documentElement.appendChild(iframe);
+            var win = iframe.contentWindow;
+            is(typeof(win.u2f.register.bind(win.u2f)), "function",
                "Should be able to bind u2f.register");
-            is(typeof(u2f.sign.bind(u2f)), "function",
+            is(typeof(win.u2f.sign.bind(win.u2f)), "function",
                "Should be able to bind u2f.sign");
+            iframe.remove();
             SimpleTest.finish();
         });
     }

dom/u2f/tests/test_polyfill_interaction.html

@@ -14,21 +14,30 @@
                               doTest);
 
     function doTest() {
+        // Need a new global for the pref to really take effect.
+        var iframe = document.createElement("iframe");
+        document.documentElement.appendChild(iframe);
+        var win = iframe.contentWindow;
         var s = document.createElement("script");
         s.textContent = `
           'use strict';
-          var savedU2f = u2f;
-          var savedRegister = savedU2f.register;
-          var savedSign = savedU2f.sign;
-          var u2f = u2f || {};
-          u2f.register = function() {};
-          u2f.sign = function() {};
-          is(u2f, savedU2f, "Should still have the right object");
-          is(u2f.register, savedRegister, "Should not allow overriding 'sign'");
-          is(u2f.sign, savedSign, "Should not allow overriding 'sign'");
-          SimpleTest.finish();
+          try {
+            var savedU2f = u2f;
+            var savedRegister = savedU2f.register;
+            var savedSign = savedU2f.sign;
+            var u2f = u2f || {};
+            u2f.register = function() {};
+            u2f.sign = function() {};
+            parent.is(u2f, savedU2f, "Should still have the right object");
+            parent.is(u2f.register, savedRegister, "Should not allow overriding 'sign'");
+            parent.is(u2f.sign, savedSign, "Should not allow overriding 'sign'");
+          } catch (e) {
+            parent.ok(false, "Threw an exception: " + e);
+          } finally {
+            parent.SimpleTest.finish();
+          }
         `;
-        document.documentElement.appendChild(s);
+        win.document.documentElement.appendChild(s);
     }
   </script>
 </head>