Add repeat_delay_ms and repeat_count as configurable parameters to the infinit scrolling benchmarks.

tools/perf/page_sets/infinite_scroll_cases.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.page import shared_page_state
 from telemetry import story
 
 TIME_TO_WAIT_BEFORE_STARTING_IN_SECONDS = 5
 
 # TODO(ulan): Remove this once crbug.com/541508 is fixed.
 STARTUP_SCRIPT = '''
     window.WebSocket = undefined;
     window.Worker = undefined;
     window.performance = undefined;'''
 
-def _ScrollAction(action_runner, scroll_amount):
+def _ScrollAction(action_runner, scroll_amount, delay, repeat):
   action_runner.Wait(TIME_TO_WAIT_BEFORE_STARTING_IN_SECONDS)
   with action_runner.CreateInteraction('Begin'):
     action_runner.tab.browser.DumpMemory()
   with action_runner.CreateInteraction('Scrolling'):
     action_runner.RepeatableBrowserDrivenScroll(
       y_scroll_distance_ratio=scroll_amount,
-      repeat_count=0)
+      repeat_delay_ms=delay,
+      repeat_count=repeat)
   with action_runner.CreateInteraction('End'):
     action_runner.tab.browser.DumpMemory()
 
 def _WaitAction(action_runner):
   action_runner.WaitForJavaScriptCondition(
     'document.body != null && '
     'document.body.scrollHeight > window.innerHeight && '
     '!document.body.addEventListener("touchstart", function() {})')
 
 def _CreateInfiniteScrollPageClass(base_page_cls):
   class DerivedSmoothPage(base_page_cls):  # pylint: disable=no-init
     def RunPageInteractions(self, action_runner):
       _WaitAction(action_runner)
-      _ScrollAction(action_runner, self.scroll_amount)
+      _ScrollAction(action_runner, self.scroll_amount, self.delay, self.repeat)
   return DerivedSmoothPage
 
 class InfiniteScrollPage(page_module.Page):
-  def __init__(self, url, page_set, name, scroll_amount, credentials=None):
+  def __init__(self, url, page_set, name, scroll_amount, delay, repeat,
+               credentials=None):
     super(InfiniteScrollPage, self).__init__(
         url=url, page_set=page_set, name=name,
         shared_page_state_class=shared_page_state.SharedPageState,
        credentials_path='data/credentials.json')
     self.credentials = credentials
     self.script_to_evaluate_on_commit = STARTUP_SCRIPT
     self.scroll_amount = scroll_amount
+    self.delay = delay
+    self.repeat = repeat
 
 class InfiniteScrollPageSet(story.StorySet):
   """ Top pages that can be scrolled for many pages. """
   def __init__(self):
     super(InfiniteScrollPageSet, self).__init__(
         archive_data_file='data/infinite_scroll.json',
         cloud_storage_bucket=story.PARTNER_BUCKET)
     # The scroll distance is chosen such that the page can be scrolled
     # continiously throught the test without hitting the end of the page.
     SCROLL_FAR = 30
     SCROLL_NEAR = 13
+    SCROLL_PAGE = 1
     pages = [
-        ('https://www.facebook.com/shakira', 'facebook', SCROLL_FAR),
-        ('https://twitter.com/taylorswift13', 'twitter', SCROLL_FAR),
-        ('http://espn.go.com/', 'espn', SCROLL_NEAR),
-        ('https://www.yahoo.com', 'yahoo', SCROLL_NEAR),
-        ('http://techcrunch.tumblr.com/', 'tumblr', SCROLL_FAR),
-        ('https://www.flickr.com/explore', 'flickr', SCROLL_FAR)
+        ('https://www.facebook.com/shakira', 'facebook', SCROLL_FAR, 0, 0),
+        ('https://twitter.com/taylorswift13', 'twitter', SCROLL_PAGE, 10, 30),
+        ('http://espn.go.com/', 'espn', SCROLL_NEAR, 0, 0),
+        ('https://www.yahoo.com', 'yahoo', SCROLL_NEAR, 0, 0),
+        ('http://techcrunch.tumblr.com/', 'tumblr', SCROLL_FAR, 0, 0),
+        ('https://www.flickr.com/explore', 'flickr', SCROLL_FAR, 0, 0)
     ]
-    for (url, name, scroll_amount) in pages:
+    for (url, name, scroll_amount, delay, repeat) in pages:
       page_class = _CreateInfiniteScrollPageClass(InfiniteScrollPage)
-      self.AddStory(page_class(url, self, name, scroll_amount))
+      self.AddStory(page_class(url, self, name, scroll_amount, delay, repeat))