Support for system-guest on cros.

tools/telemetry/telemetry/core/chrome/cros_browser_backend.py

 # Copyright (c) 2012 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 logging
 import os
 import subprocess
 
 from telemetry.core import exceptions
 from telemetry.core import util
 from telemetry.core.chrome import browser_backend
@@ skipping 93 matching lines @@
 
     # chrome_branch_number is set in _PostBrowserStartupInitialization.
     # Without --skip-hwid-check (introduced in crrev.com/203397), devices/VMs
     # will be stuck on the bad hwid screen.
     if self.chrome_branch_number <= 1500 and not self.hwid:
       raise exceptions.LoginException(
           'Hardware id not set on device/VM. --skip-hwid-check not supported '
           'with chrome branches 1500 or earlier.')
 
     if self._is_guest:
+      pid = self.pid
       cros_util.NavigateGuestLogin(self, cri)
       # Guest browsing shuts down the current browser and launches an incognito
-      # browser, which we need to wait for.
+      # browser in a separate process, which we need to wait for.
+      util.WaitFor(lambda: pid != self.pid, 10)
       self._WaitForBrowserToComeUp()
     else:
       cros_util.NavigateLogin(self)
 
     logging.info('Browser is up!')
 
   def GetBrowserStartupArgs(self):
     self.webpagereplay_remote_http_port = self._cri.GetRemotePort()
     self.webpagereplay_remote_https_port = self._cri.GetRemotePort()
 
@@ skipping 105 matching lines @@
   @property
   def url(self):
     assert self._proc
     return 'http://localhost:%i' % self._host_port
 
   def Close(self):
     if self._proc:
       self._proc.kill()
       self._proc = None