Refactor xvfb.py

testing/scripts/run_telemetry_as_googletest.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """Runs isolate bundled Telemetry unittests.
 
 This script attempts to emulate the contract of gtest-style tests
 invoked via recipes. The main contract is that the caller passes the
 argument:
@@ skipping 30 matching lines @@
   args, rest_args = parser.parse_known_args()
   # Remove the chartjson extra arg until this script cares about chartjson
   # results from telemetry
   index = 0
   for arg in rest_args:
     if '--isolated-script-test-chartjson-output' in arg:
       rest_args.pop(index)
       break
     index += 1
 
-  xvfb_proc = None
-  openbox_proc = None
-  xcompmgr_proc = None
-  env = os.environ.copy()
-  if args.xvfb and xvfb.should_start_xvfb(env):
-    xvfb_proc, openbox_proc, xcompmgr_proc = xvfb.start_xvfb(env=env,
-                                                             build_dir='.')
-    assert xvfb_proc and openbox_proc and xcompmgr_proc, 'Failed to start xvfb'
   # Compatibility with gtest-based sharding.
   total_shards = None
   shard_index = None
+  env = os.environ.copy()
   if 'GTEST_TOTAL_SHARDS' in env:
     total_shards = int(env['GTEST_TOTAL_SHARDS'])
     del env['GTEST_TOTAL_SHARDS']
   if 'GTEST_SHARD_INDEX' in env:
     shard_index = int(env['GTEST_SHARD_INDEX'])
     del env['GTEST_SHARD_INDEX']
   sharding_args = []
   if total_shards is not None and shard_index is not None:
     sharding_args = [
       '--total-shards=%d' % total_shards,
       '--shard-index=%d' % shard_index
     ]
-  try:
-    return common.run_command([sys.executable] + rest_args + sharding_args + [
-      '--write-full-results-to', args.isolated_script_test_output], env=env)
-  finally:
-    xvfb.kill(xvfb_proc)
-    xvfb.kill(openbox_proc)
-    xvfb.kill(xcompmgr_proc)
-
+  cmd = [sys.executable] + rest_args + sharding_args + [
+      '--write-full-results-to', args.isolated_script_test_output]
+  if args.xvfb:
+    return xvfb.run_executable(cmd, '.', env)
+  else:
+    return common.run_command(cmd, env=env)
 
 
 # This is not really a "script test" so does not need to manually add
 # any additional compile targets.
 def main_compile_targets(args):
   json.dump([], args.output)
 
 
 if __name__ == '__main__':
   # Conform minimally to the protocol defined by ScriptTest.
   if 'compile_targets' in sys.argv:
     funcs = {
       'run': None,
       'compile_targets': main_compile_targets,
     }
     sys.exit(common.run_script(sys.argv[1:], funcs))
   sys.exit(main())