Code review comment for lp:~canonical-platform-qa/webbrowser-app/fix_base_class

Un-approving. On my desktop, this breaks running one single test case. Running all test cases in one given file/class still works, but passing the fully-qualified name of a test case (e.g. webbrowser_app.tests.test_tabs.TestTabsView.test_switch_tabs) to `autopilot3 run` fails with the following error:

Traceback (most recent call last):
  File "/home/osomon/dev/phablet/browser/webbrowser-app/tests/autopilot/webbrowser_app/tests/test_tabs.py", line 36, in setUp
    super(TestTabsView, self).setUp()
  File "/home/osomon/dev/phablet/browser/webbrowser-app/tests/autopilot/webbrowser_app/tests/__init__.py", line 188, in setUp
    self.assert_home_page_eventually_loaded()
  File "/home/osomon/dev/phablet/browser/webbrowser-app/tests/autopilot/webbrowser_app/tests/__init__.py", line 191, in assert_home_page_eventually_loaded
    self.main_window.wait_until_page_loaded(self.url)
  File "/home/osomon/dev/phablet/browser/webbrowser-app/tests/autopilot/webbrowser_app/tests/__init__.py", line 109, in main_window
    return self.app.main_window
  File "/usr/lib/python3/dist-packages/autopilot/introspection/dbus.py", line 416, in __getattr__
    (self.__class__.__name__, name))
AttributeError: Class 'webbrowser-app' has no attribute 'main_window'.