Experiment with blocking resolution of HTTP URLs containing '\n' and '<'.

third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js

Index: third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js
diff --git a/third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js b/third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js
index 7d5ad6d10d025e836701eeb96754bad2e17076ed..100bcba7b5184a12955c6c99ce21c483301ef446 100644
--- a/third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js
+++ b/third_party/WebKit/LayoutTests/http/tests/security/dangling-markup/resources/helper.js
@@ -4,6 +4,16 @@ function assert_no_message_from_frame(test, frame) {
   }));
 }
 
+function appendFrameAndGetElement(test, frame) {
+  return new Promise((resolve, reject) => {
+    frame.onload = test.step_func(_ => {
+      frame.onload = null;
+      resolve(frame.contentDocument.querySelector('#dangling'));
+    });
+    document.body.appendChild(frame);
+  });
+}
+
 function appendAndSubmit(test, frame) {
   return new Promise((resolve, reject) => {
     frame.onload = test.step_func(_ => {
@@ -30,6 +40,22 @@ function assert_no_submission(test, frame) {
     }));
 }
 
+function assert_img_loaded(test, frame) {
+  appendFrameAndGetElement(test, frame)
+    .then(test.step_func_done(img => {
+      assert_equals(img.naturalHeight, 103, "Height");
+      assert_equals(img.naturalWidth, 76, "Width");
+    }));
+}
+
+function assert_img_not_loaded(test, frame) {
+  appendFrameAndGetElement(test, frame)
+    .then(test.step_func_done(img => {
+      assert_equals(img.naturalHeight, 0, "Height");
+      assert_equals(img.naturalWidth, 0, "Width");
+    }));
+}
+
 function createFrame(markup) {
   var i = document.createElement('iframe');
   i.srcdoc = `${markup}sekrit`;