predictors: browser test for client-side redirect.

chrome/test/data/predictors/javascript_redirect.js

Index: chrome/test/data/predictors/javascript_redirect.js
diff --git a/chrome/test/data/predictors/javascript_redirect.js b/chrome/test/data/predictors/javascript_redirect.js
new file mode 100644
index 0000000000000000000000000000000000000000..02f2e53180347e062ce01537e4f124e718f194a2
--- /dev/null
+++ b/chrome/test/data/predictors/javascript_redirect.js
@@ -0,0 +1,17 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function getUrlParameters() {
+  var result = {};
+  var parts = window.location.search.substring(1).split('&');
+  for (var i = 0; i < parts.length; i++) {
+    var pair = parts[i].split('=');
+    result[pair[0]] = decodeURIComponent(pair[1]);
+  }
+  return result;
+}
+
+var params = getUrlParameters();
+var redirectUrl = params["url"];
+location.href = redirectUrl;