Add an "in_unit_test_mode" attribute to the environment. Use this to default output format to 'gtes…

content/test/gpu/gpu_tests/context_lost.py

 # Copyright (c) 2013 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 os
 
 from telemetry import benchmark as benchmark_module
 from telemetry.core import exceptions
 from telemetry.core import util
 from telemetry.page import page
 from telemetry.page import page_set
@@ skipping 24 matching lines @@
       domAutomationController._succeeded = false;
       domAutomationController._finished = true;
     }
   }
 
   window.domAutomationController = domAutomationController;
   console.log("Harness injected.");
 """
 
 class _ContextLostValidator(page_test.PageTest):
+  options = {'output_format': 'gtest'}
+
   def __init__(self):
     # Strictly speaking this test doesn't yet need a browser restart
     # after each run, but if more tests are added which crash the GPU
     # process, then it will.
     super(_ContextLostValidator, self).__init__(
       needs_browser_restart_after_each_page=True)
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs(
         '--disable-domain-blocking-for-3d-apis')
@@ skipping 157 matching lines @@
   def CreatePageSet(self, options):
     ps = page_set.PageSet(
       file_path=data_path,
       user_agent_type='desktop',
       serving_dirs=set(['']))
     ps.AddPage(WebGLContextLostFromGPUProcessExitPage(ps, ps.base_dir))
     ps.AddPage(WebGLContextLostFromLoseContextExtensionPage(ps, ps.base_dir))
     ps.AddPage(WebGLContextLostFromQuantityPage(ps, ps.base_dir))
     ps.AddPage(WebGLContextLostFromSelectElementPage(ps, ps.base_dir))
     return ps