Add mobile version of v8.infinite_scroll benchmark.

tools/perf/page_sets/login_helpers/mobile_facebook_login.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 page_sets.login_helpers import login_utils
 
 
-def LoginGoogleAccount(action_runner, credential,
-                       credentials_path=login_utils.DEFAULT_CREDENTIAL_PATH):
-  """Logs in into Google account.
+def LoginAccount(
+    action_runner, credential,
+    credentials_path=login_utils.DEFAULT_CREDENTIAL_PATH):
+  """Logs in into mobile Facebook account.
 
-  This function navigates the tab into Google's login page and logs in a user
+  This function navigates the tab into Facebook's login page and logs in a user
   using credentials in |credential| part of the |credentials_path| file.
 
   Args:
     action_runner: Action runner responsible for running actions on the page.
     credential: The credential to retrieve from the credentials file
         (type string).
     credentials_path: The string that specifies the path to credential file.
 
   Raises:
     exceptions.Error: See ExecuteJavaScript()
     for a detailed list of possible exceptions.
   """
   account_name, password = login_utils.GetAccountNameAndPassword(
       credential, credentials_path=credentials_path)
 
   action_runner.Navigate(
-       'https://accounts.google.com/ServiceLogin?continue='
-       'https%3A%2F%2Faccounts.google.com%2FManageAccount')
-  login_utils.InputForm(action_runner, account_name, input_id='Email',
-                        form_id='gaia_firstform')
-  action_runner.ClickElement(selector='#gaia_firstform #next')
-  login_utils.InputForm(action_runner, password, input_id='Passwd')
-  action_runner.ClickElement(selector='#signIn')
-  action_runner.WaitForElement(text='My Account')
+       'https://m.facebook.com/login?continue=https%3A%2F%2Fm.facebook.com')
+  login_utils.InputWithSelector(action_runner, account_name, '[name=email]')
+  login_utils.InputWithSelector(action_runner, password, '[name=pass]')
+  action_runner.ClickElement(selector='[name=login]')
+  action_runner.WaitForElement(text='OK')
+  action_runner.ClickElement(text='OK')
+  action_runner.WaitForNavigate()