sandwich: Builds a script to pull the metrics from the traces

tools/android/loading/run_sandwich.py

 #! /usr/bin/env 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.
 
 """Instructs Chrome to load series of web pages and reports results.
 
 When running Chrome is sandwiched between preprocessed disk caches and
 WepPageReplay serving all connections.
 
@@ skipping 13 matching lines @@
 from devil.android import device_utils
 
 sys.path.append(os.path.join(_SRC_DIR, 'build', 'android'))
 from pylib import constants
 import devil_chromium
 
 import device_setup
 import devtools_monitor
 import json
 import page_track
+import pull_sandwich_metrics
 import tracing
 
 
 _JOB_SEARCH_PATH = 'sandwich_jobs'
 
 # Directory name under --output to save the cache from the device.
 _CACHE_DIRECTORY_NAME = 'cache'
 
 # Name of cache subdirectory on the device where the cache index is stored.
 _INDEX_DIRECTORY_NAME = 'index-dir'
@@ skipping 38 matching lines @@
   Args:
     events: a dict as returned by TracingTrack.ToJsonDict()
     directory: directory name contining all traces
     subdirectory: directory name to create this particular trace in
   """
   target_directory = os.path.join(directory, subdirectory)
   filename = os.path.join(target_directory, 'trace.json')
   try:
     os.makedirs(target_directory)
     with open(filename, 'w') as f:
-      json.dump({'traceEvents': events['events'], 'metadata': {}}, f)
+      json.dump({'traceEvents': events['events'], 'metadata': {}}, f, indent=2)
   except IOError:
     logging.warning('Could not save a trace: %s' % filename)
     # Swallow the exception.
 
 
 def _UpdateTimestampFromAdbStat(filename, stat):
   os.utime(filename, (stat.st_time, stat.st_time))
 
 
 def _SaveBrowserCache(device, output_directory):
@@ skipping 78 matching lines @@
     pages_loaded = 0
     for iteration in xrange(args.repeat):
       for url in job_urls:
         with device_setup.DeviceConnection(
             device=device,
             additional_flags=additional_flags) as connection:
           if iteration == 0 and pages_loaded == 0 and args.save_cache:
             connection.ClearCache()
           page_track.PageTrack(connection)
           tracing_track = tracing.TracingTrack(connection,
-              categories='blink,cc,netlog,renderer.scheduler,toplevel,v8')
+              categories=pull_sandwich_metrics.CATEGORIES)
           connection.SetUpMonitoring()
           connection.SendAndIgnoreResponse('Page.navigate', {'url': url})
           connection.StartMonitoring()
           pages_loaded += 1
           _SaveChromeTrace(tracing_track.ToJsonDict(), args.output,
               str(pages_loaded))
 
   if args.save_cache:
     # Move Chrome to background to allow it to flush the index.
     device.adb.Shell('am start com.google.android.launcher')
     time.sleep(_TIME_TO_DEVICE_IDLE_SECONDS)
     device.KillAll(_CHROME_PACKAGE, quiet=True)
     time.sleep(_TIME_TO_DEVICE_IDLE_SECONDS)
     _SaveBrowserCache(device, args.output)
 
 
 if __name__ == '__main__':
   sys.exit(main())