Use Systrace tracing controller in profile_chrome

systrace/profile_chrome/chrome_startup_tracing_agent.py

 # 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.
 
 import optparse
 import os
 import py_utils
 import re
 
 from devil.android import flag_changer
@@ skipping 42 matching lines @@
           extras={'create_new_tab': True})
     self._device.StartActivity(launch_intent, blocking=True)
 
   def _TearDownTracing(self):
     self._flag_changer.Restore()
 
   @py_utils.Timeout(tracing_agents.START_STOP_TIMEOUT)
   def StartAgentTracing(self, config, timeout=None):
     self._SetupTracing()
     self._logcat_monitor.Start()
+    return True
 
   @py_utils.Timeout(tracing_agents.START_STOP_TIMEOUT)
   def StopAgentTracing(self, timeout=None):
     try:
       self._trace_file = self._logcat_monitor.WaitFor(
           self._trace_finish_re).group(1)
     finally:
       self._TearDownTracing()
+    return True
 
   @py_utils.Timeout(tracing_agents.GET_RESULTS_TIMEOUT)
   def GetResults(self, timeout=None):
     with open(self._PullTrace(), 'r') as f:
       trace_data = f.read()
     return trace_result.TraceResult('traceEvents', trace_data)
 
   def _PullTrace(self):
     trace_file = self._trace_file.replace('/storage/emulated/0/', '/sdcard/')
     host_file = os.path.join(os.path.curdir, os.path.basename(trace_file))
     self._device.PullFile(trace_file, host_file)
     return host_file
 
   def SupportsExplicitClockSync(self):
     return False
 
   def RecordClockSyncMarker(self, sync_id, did_record_sync_marker_callback):
+    # pylint: disable=unused-argument
     assert self.SupportsExplicitClockSync(), ('Clock sync marker cannot be '
         'recorded since explicit clock sync is not supported.')
 
 
 class ChromeStartupConfig(tracing_agents.TracingConfig):
-  def __init__(self):
+  def __init__(self, device, package_info, cold, url, chrome_categories,
+               chrome_startup):
     tracing_agents.TracingConfig.__init__(self)
+    self.device = device
+    self.package_info = package_info
+    self.cold = cold
+    self.url = url
+    self.chrome_categories = chrome_categories
+    self.chrome_startup = chrome_startup
 
 
+def try_create_agent(config):
+  if config.chrome_startup:
+    return ChromeStartupTracingAgent(config.device, config.package_info,
+                                     config.cold, config.url)
+  return False

[Sami, 2016/09/01 12:15:59]

I think it would be more pythonic to either return the agent instance or None,
not a bool.

[washingtonp, 2016/09/01 17:44:41]

Done.

+
 def add_options(parser):
   options = optparse.OptionGroup(parser, 'Chrome startup tracing')
   options.add_option('--url', help='URL to visit on startup. Default: '
                      'https://www.google.com. An empty URL launches Chrome '
                      'with a MAIN action instead of VIEW.',
                      default='https://www.google.com', metavar='URL')
   options.add_option('--cold', help='Flush the OS page cache before starting '
                      'the browser. Note that this require a device with root '
                      'access.', default=False, action='store_true')
+  options.chrome_startup = True

[Sami, 2016/09/01 12:15:59]

I wouldn't expect a function called add_options to also set some options. Should
we do this elsewhere -- in the front-end perhaps?

[washingtonp, 2016/09/01 17:44:41]

Done.

   return options
 
 def get_config(options):
-  # pylint: disable=unused-argument
-  return ChromeStartupConfig()
+  return ChromeStartupConfig(options.device, options.package_info,
+                             options.cold, options.url,
+                             options.chrome_categories, options.chrome_startup)