Migrate web-page-replay-go files

web_page_replay_go/deterministic.js

+// 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.
+
+'use strict';
+
+(function () {
+  var random_count = 0;
+  var random_count_threshold = 25;
+  var random_seed = 0.462;
+  Math.random = function() {
+    random_count++;
+    if (random_count > random_count_threshold){
+     random_seed += 0.1;
+     random_count = 1;
+    }
+    return (random_seed % 1);
+  };
+  if (typeof(crypto) == 'object' &&
+      typeof(crypto.getRandomValues) == 'function') {
+    crypto.getRandomValues = function(arr) {
+      var scale = Math.pow(256, arr.BYTES_PER_ELEMENT);
+      for (var i = 0; i < arr.length; i++) {
+        arr[i] = Math.floor(Math.random() * scale);
+      }
+      return arr;
+    };
+  }
+})();
+(function () {
+  var date_count = 0;
+  var date_count_threshold = 25;
+  var orig_date = Date;
+  var time_seed = 1204251968254;

[nednguyen, 2017/06/16 17:13:05]

at some point we should fix the time_see here to be a place holder that is to be
filled by time of the recording.

+  Date = function() {
+    if (this instanceof Date) {
+      date_count++;
+      if (date_count > date_count_threshold){
+        time_seed += 50;
+        date_count = 1;
+      }
+      switch (arguments.length) {
+      case 0: return new orig_date(time_seed);
+      case 1: return new orig_date(arguments[0]);
+      default: return new orig_date(arguments[0], arguments[1],
+         arguments.length >= 3 ? arguments[2] : 1,
+         arguments.length >= 4 ? arguments[3] : 0,
+         arguments.length >= 5 ? arguments[4] : 0,
+         arguments.length >= 6 ? arguments[5] : 0,
+         arguments.length >= 7 ? arguments[6] : 0);
+      }
+    }
+    return new Date().toString();
+  };
+  Date.__proto__ = orig_date;
+  Date.prototype = orig_date.prototype;
+  Date.prototype.constructor = Date;
+  orig_date.now = function() {
+    return new Date().getTime();
+  };
+  orig_date.prototype.getTimezoneOffset = function() {
+    var dst2010Start = 1268560800000;
+    var dst2010End = 1289120400000;
+    if (this.getTime() >= dst2010Start && this.getTime() < dst2010End)
+      return 420;
+    return 480;
+  };
+})();