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

content/test/gpu/run_gpu_test

Index: content/test/gpu/run_gpu_test
diff --git a/content/test/gpu/run_gpu_test b/content/test/gpu/run_gpu_test
new file mode 100755
index 0000000000000000000000000000000000000000..2bb5e865e5bcec182c3c3e5a930f1b8555e9fdce
--- /dev/null
+++ b/content/test/gpu/run_gpu_test
@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+# Copyright 2014 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
+import subprocess
+import sys
+
+if __name__ == '__main__':
+  path_to_script = os.path.dirname(os.path.abspath(__file__))
+  command_name = os.path.join(path_to_script, 'run_gpu_test.py')
+  command = [command_name, '--output-format=gtest']
+  command.extend(sys.argv[1:])
+  subprocess.call(command)