moebius#231: Consider blocking top level window data: URIs (tests)

https://github.com/MoonchildProductions/moebius/pull/231

dom/base/test/file_ipc_messagemanager_blob.html

@@ -0,0 +1 @@
+<!DOCTYPE HTML><html><body></body></html>

dom/base/test/mochitest.ini

@@ -676,6 +676,7 @@ skip-if = (toolkit == 'android') # Android: Bug 775227
 [test_intersectionobservers.html]
 skip-if = true # Track Bug 1320704
 [test_ipc_messagemanager_blob.html]
+support-files = file_ipc_messagemanager_blob.html
 [test_link_prefetch.html]
 skip-if = !e10s # Track Bug 1281415
 [test_link_stylesheet.html]

dom/base/test/test_ipc_messagemanager_blob.html

@@ -14,8 +14,7 @@
 
     SimpleTest.waitForExplicitFinish();
 
-    const childFrameURL =
-      "data:text/html,<!DOCTYPE HTML><html><body></body></html>";
+    const childFrameURL = "file_ipc_messagemanager_blob.html";
 
     function childFrameScript() {
       "use strict";

dom/base/test/test_x-frame-options.html

@@ -147,7 +147,11 @@ var testFrameInDataURI = function() {
 SimpleTest.waitForExplicitFinish();
 
 // load the test harness
-document.getElementById("harness").src = "file_x-frame-options_main.html";
+SpecialPowers.pushPrefEnv({
+  "set": [["security.data_uri.block_toplevel_data_uri_navigations", false],]
+}, function() {
+  document.getElementById("harness").src = "file_x-frame-options_main.html";
+});
 
 </script>
 </pre>