Delete top_25_pages page set since unused

The top_25_pages page set is not used in any benchmarks or inherited by
any other classes, therefore remove it.

Bug: 760553
Change-Id: I37849b76f92aab88e124ac2086b596782a3b0546
Reviewed-on: https://chromium-review.googlesource.com/1072447Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561942}

tools/perf/page_sets/top_25_pages.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
-from telemetry.page import shared_page_state
-from telemetry import story
-
-from page_sets import top_pages
-
-
-class Top25PageSet(story.StorySet):
-
-  """ Page set consists of top 25 pages with only navigation actions. """
-
-  def __init__(self):
-    super(Top25PageSet, self).__init__(
-        archive_data_file='data/top_25.json',
-        cloud_storage_bucket=story.PARTNER_BUCKET)
-
-    shared_desktop_state = shared_page_state.SharedDesktopPageState
-    self.AddStory(top_pages.GoogleWebSearchPage(self, shared_desktop_state))
-    self.AddStory(top_pages.GmailPage(self, shared_desktop_state))
-    self.AddStory(top_pages.GoogleCalendarPage(self, shared_desktop_state))
-    self.AddStory(
-        top_pages.GoogleImageSearchPage(self, shared_desktop_state))
-    self.AddStory(top_pages.GoogleDocPage(self, shared_desktop_state))
-    self.AddStory(top_pages.GooglePlusPage(self, shared_desktop_state))
-    self.AddStory(top_pages.YoutubePage(self, shared_desktop_state))
-    self.AddStory(top_pages.BlogspotPage(self, shared_desktop_state))
-    self.AddStory(top_pages.WordpressPage(self, shared_desktop_state))
-    self.AddStory(top_pages.FacebookPage(self, shared_desktop_state))
-    self.AddStory(top_pages.LinkedinPage(self, shared_desktop_state))
-    self.AddStory(top_pages.WikipediaPage(self, shared_desktop_state))
-    self.AddStory(top_pages.TwitterPage(self, shared_desktop_state))
-    self.AddStory(top_pages.PinterestPage(self, shared_desktop_state))
-    self.AddStory(top_pages.ESPNPage(self, shared_desktop_state))
-    self.AddStory(top_pages.WeatherPage(self, shared_desktop_state))
-    self.AddStory(top_pages.YahooGamesPage(self, shared_desktop_state))
-
-    other_urls = [
-        # Why: #1 news worldwide (Alexa global)
-        'http://news.yahoo.com',
-        # Why: #2 news worldwide
-        'http://www.cnn.com',
-        # Why: #1 world commerce website by visits; #3 commerce in the US by
-        # time spent
-        'http://www.amazon.com',
-        # Why: #1 commerce website by time spent by users in US
-        'http://www.ebay.com',
-        # Why: #1 Alexa recreation
-        'http://booking.com',
-        # Why: #1 Alexa reference
-        'http://answers.yahoo.com',
-        # Why: #1 Alexa sports
-        'http://sports.yahoo.com/',
-        # Why: top tech blog
-        'http://techcrunch.com'
-    ]
-
-    for url in other_urls:
-      self.AddStory(
-          page.Page(url, self, shared_page_state_class=shared_desktop_state,
-                    name=url))