Telemetry: Create new profile creator large_profile_creator.

tools/perf/profile_creators/cookie_profile_extender.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.
+import multiprocessing
+import os
+import sqlite3
+
+from profile_creators import fast_navigation_profile_extender
+from profile_creators import profile_safe_url_list
+
+class CookieProfileExtender(
+    fast_navigation_profile_extender.FastNavigationProfileExtender):
+  """This extender performs a large number of navigations (up to 500), with the
+  goal of filling out the cookie database.
+
+  By default, Chrome purges the cookie DB down to 3300 cookies. However, it
+  won't purge cookies accessed in the last month. This means the extender needs
+  to be careful not to create an artificially high number of cookies.
+  """
+  _COOKIE_DB_EXPECTED_SIZE = 3300
+
+  def __init__(self):
+    # The rate limiting factors are fetching network resources and executing
+    # javascript. There's not much to be done about the former, and having one
+    # tab per logical core appears close to optimum for the latter.
+    maximum_batch_size = multiprocessing.cpu_count()
+    super(CookieProfileExtender, self).__init__(maximum_batch_size)
+
+    # A list of urls that have not yet been navigated to. This list will shrink
+    # over time. Each navigation will add a diminishing number of new cookies,
+    # since there's a high probability that the cookie is already present. If
+    # the cookie DB isn't full by 500 navigations, just give up.
+    self._navigation_urls = profile_safe_url_list.GetShuffledSafeUrls()[0:500]
+
+  def GetUrlIterator(self):
+    """Superclass override."""
+    return iter(self._navigation_urls)
+
+  def ShouldExitAfterBatchNavigation(self):
+    """Superclass override."""
+    return self._IsCookieDBFull()
+
+  @staticmethod
+  def _CookieCountInDB(db_path):
+    """The number of cookies in the db at |db_path|."""
+    connection = sqlite3.connect(db_path)
+    try:
+      cursor = connection.cursor()
+      cursor.execute("select count(*) from cookies")
+      cookie_count = cursor.fetchone()[0]
+    except:
+      raise
+    finally:
+      connection.close()
+    return cookie_count
+
+  def _IsCookieDBFull(self):
+    """Chrome does not immediately flush cookies to its database. It's possible
+    that this method will return a false negative."""
+    cookie_db_path = os.path.join(self.profile_path, "Default", "Cookies")
+    try:
+      cookie_count = CookieProfileExtender._CookieCountInDB(cookie_db_path)
+    except sqlite3.OperationalError:
+      # There will occasionally be contention for the SQLite database. This
+      # shouldn't happen often, so ignore the errors.
+      return False
+
+    return cookie_count > CookieProfileExtender._COOKIE_DB_EXPECTED_SIZE