Fetch the first tab inside the browser startup retry loop.

content/test/gpu/gpu_tests/gpu_process_integration_test.py

 # Copyright 2017 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 sys
 
 from gpu_tests import gpu_integration_test
 from gpu_tests import gpu_process_expectations
@@ skipping 67 matching lines @@
 
   @classmethod
   def RestartBrowserIfNecessaryWithArgs(cls, browser_args):
     if not browser_args:
       browser_args = []
     if set(browser_args) != cls._last_launched_browser_args:
       logging.info('Restarting browser with arguments: ' + str(browser_args))
       cls.StopBrowser()
       cls.CustomizeBrowserArgs(browser_args)
       cls.StartBrowser()
-      cls.tab = cls.browser.tabs[0]
 
   @classmethod
   def _CreateExpectations(cls):
     return gpu_process_expectations.GpuProcessExpectations()
 
   @classmethod
   def GenerateGpuTests(cls, options):
     # The browser test runner synthesizes methods with the exact name
     # given in GenerateGpuTests, so in order to hand-write our tests but
     # also go through the _RunGpuTest trampoline, the test needs to be
@@ skipping 420 matching lines @@
   def _GpuProcess_software_gpu_process(self, test_path):
     # Hit exception from id 50 from kSoftwareRenderingListJson.
     self.RestartBrowserIfNecessaryWithArgs([
       '--gpu-testing-vendor-id=0x10de',
       '--gpu-testing-device-id=0x0de1',
       '--gpu-testing-gl-vendor=VMware',
       '--gpu-testing-gl-renderer=SVGA3D',
       '--gpu-testing-gl-version=2.1 Mesa 10.1'])
     self._Navigate(test_path)
     self._VerifyGpuProcessPresent()