[tools/perf] Add dummy benchmark that produces Gaussian value with a known mean and std

tools/perf/page_sets/dummy_story_set.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.
+from telemetry.page import page as page_module
+from telemetry import story
+
+
+class DummyPage(page_module.Page):
+
+  def __init__(self, page_set):
+    super(DummyPage, self).__init__(
+      url='file://dummy_page.html',
+      page_set=page_set)
+
+  def PerformPageInteractions(self, action_runner):
+    assert action_runner.EvaluateJavaScript('1 + window.__dummy_value') == 2
+
+
+class DummyStorySet(story.StorySet):
+
+  def __init__(self):
+    super(DummyStorySet, self).__init__()
+    self.AddStory(DummyPage(self))