Remove Skia's forked buildbot code

slave/skia_slave_scripts/page_sets/skia_gmail_nexus10.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.
-# pylint: disable=W0401,W0614
-
-
-from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
-
-
-class SkiaBuildbotDesktopPage(page_module.Page):
-
-  def __init__(self, url, page_set):
-    super(SkiaBuildbotDesktopPage, self).__init__(url=url, page_set=page_set)
-    self.user_agent_type = 'tablet'
-    self.archive_data_file = 'data/skia_gmail_nexus10.json'
-    self.credentials_path = 'data/credentials.json'
-    self.credentials = 'google'
-
-  def RunSmoothness(self, action_runner):
-    action_runner.ScrollElement()
-
-  def RunNavigateSteps(self, action_runner):
-    action_runner.NavigateToPage(self)
-    action_runner.Wait(10)
-
-
-class SkiaBuildbotPageSet(page_set_module.PageSet):
-
-  """ Pages designed to represent the median, not highly optimized web """
-
-  def __init__(self):
-    super(SkiaBuildbotPageSet, self).__init__(
-      user_agent_type='tablet',
-      credentials_path = 'data/credentials.json',
-      archive_data_file='data/skia_gmail_nexus10.json')
-
-    urls_list = [
-      # Why: productivity, top google properties
-      'https://mail.google.com/mail/',
-    ]
-
-    for url in urls_list:
-      self.AddPage(SkiaBuildbotDesktopPage(url, self))