sandwich: Refactor to use more existing code.

tools/android/loading/trace_recorder.py

 #! /usr/bin/python
 # 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.
 
 """Loading trace recorder."""
 
 import argparse
 import datetime
 import json
@@ skipping 12 matching lines @@
 import devil_chromium
 
 import device_setup
 import devtools_monitor
 import loading_trace
 import page_track
 import request_track
 import tracing
 
 
-def MonitorUrl(connection, url, clear_cache=False):
+def MonitorUrl(connection, url, clear_cache=False,
+               categories=tracing.DEFAULT_CATEGORIES):
   """Monitor a URL via a trace recorder.
 
   Args:
     connection: A device_monitor.DevToolsConnection instance.
     url: url to navigate to as string.
     clear_cache: boolean indicating if cache should be cleared before loading.
 
   Returns:
     loading_trace.LoadingTrace.
   """
   page = page_track.PageTrack(connection)
   request = request_track.RequestTrack(connection)
-  trace = tracing.TracingTrack(connection)
+  trace = tracing.TracingTrack(connection, categories=categories)
   connection.SetUpMonitoring()
   if clear_cache:
     connection.ClearCache()
   connection.SendAndIgnoreResponse('Page.navigate', {'url': url})
   connection.StartMonitoring()
   metadata = {'date': datetime.datetime.utcnow().isoformat(),
               'seconds_since_epoch': time.time()}
   return loading_trace.LoadingTrace(url, metadata, page, request, trace)
 
 def RecordAndDumpTrace(device, url, output_filename):
@@ skipping 13 matching lines @@
   args = parser.parse_args()
   url = args.url
   if not url.startswith('http'):
     url = 'http://' + url
   device = device_utils.DeviceUtils.HealthyDevices()[0]
   RecordAndDumpTrace(device, url, args.output)
 
 
 if __name__ == '__main__':
   main()