[Telemetry refactor] Drop "2" from method calls to JS API

tools/perf/page_sets/mobile_memory.py

 # Copyright 2014 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
 
 
 class MobileMemoryPage(page_module.Page):
 
@@ skipping 41 matching lines @@
       action_runner.ScrollPage()
     action_runner.Wait(3)
     with action_runner.CreateGestureInteraction('ScrollAction'):
       action_runner.ScrollPage()
     action_runner.Wait(3)
     with action_runner.CreateGestureInteraction('ScrollAction'):
       action_runner.ScrollPage()
     action_runner.Wait(3)
     with action_runner.CreateGestureInteraction('ScrollAction'):
       action_runner.ScrollPage()
-    action_runner.WaitForJavaScriptCondition2(
+    action_runner.WaitForJavaScriptCondition(
         'document.getElementById("rg_s").childElementCount > 300')
 
 
 class ScrollPage(MobileMemoryPage):
 
   def __init__(self, url, page_set):
     super(ScrollPage, self).__init__(url=url, page_set=page_set)
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateGestureInteraction('ScrollAction'):
@@ skipping 16 matching lines @@
       # Why: Renderer process memory bloat
       'http://techcrunch.com',
       # pylint: disable=line-too-long
       'http://techcrunch.com/2014/02/17/pixel-brings-brings-old-school-video-game-art-to-life-in-your-home/',
       'http://techcrunch.com/2014/02/15/kickstarter-coins-2/',
       'http://techcrunch.com/2014/02/15/was-y-combinator-worth-it/',
     ]
 
     for url in urls_list:
       self.AddStory(ScrollPage(url, self))