telemetry: Create a safe url generator.

tools/perf/profile_creators/profile_safe_url_list.py

+# Copyright 2015 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.
+import json
+import os
+import random
+
+
+def GetShuffledSafeUrls():
+  """Returns a deterministic shuffling of safe urls. The profile generators
+  access the urls in order, and the urls are grouped by domain. The shuffling
+  reduces the load on external servers."""
+  random.seed(0)
+  url_list_copy = list(_GetSafeUrls())
+  random.shuffle(url_list_copy)
+  return url_list_copy
+
+
+def _GetSafeUrls():
+  """Returns a list of safe urls by loading them from a pre-generated file."""
+  safe_url_dir = os.path.dirname(os.path.realpath(__file__))
+  safe_url_path = os.path.join(safe_url_dir, "profile_safe_url_list.json")
+  with open(safe_url_path, 'r') as safe_url_file:
+    return json.load(safe_url_file)