(Reland) Port WebGL extension availability tests to the integration test harness.

content/test/gpu/gpu_tests/gpu_integration_test.py

 # Copyright 2016 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
 
 from telemetry.testing import serially_executed_browser_test_case
 from telemetry.util import screenshot
 
 from gpu_tests import exception_formatter
@@ skipping 50 matching lines @@
   def _RunGpuTest(self, url, test_name, *args):
     temp_page = _EmulatedPage(url, test_name)
     expectations = self.__class__.GetExpectations()
     expectation = expectations.GetExpectationForPage(
       self.browser, temp_page)
     if expectation == 'skip':
       # skipTest in Python's unittest harness raises an exception, so
       # aborts the control flow here.
       self.skipTest('SKIPPING TEST due to test expectations')
     try:
+      # TODO(nednguyen): For some reason the arguments are getting wrapped
+      # in another tuple sometimes (like in the WebGL extension tests).
+      # Perhaps only if multiple arguments are yielded in the test
+      # generator?
+      if len(args) == 1 and isinstance(args[0], tuple):
+        args = args[0]
       self.RunActualGpuTest(url, *args)
     except Exception:
       if expectation == 'pass':
         # This is not an expected exception or test failure, so print
         # the detail to the console.
         exception_formatter.PrintFormattedException()
         # This failure might have been caused by a browser or renderer
         # crash, so restart the browser to make sure any state doesn't
         # propagate to the next test iteration.
         self._RestartBrowser('unexpected test failure')
@@ skipping 73 matching lines @@
 
   def setUp(self):
     try:
       self.tab = self.browser.tabs[0]
     except Exception:
       # restart the browser to make sure a failure in a test doesn't
       # propagate to the next test iteration.
       logging.exception("Failure during browser startup")
       self._RestartBrowser('failure in setup')
       raise