sandwich: Adds command line flag to disable WPR injections

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 278 matching lines @@
                       help='How many times to run the job')
   parser.add_argument('--cache-op',
                       choices=['clear', 'save', 'push'],
                       default='clear',
                       help='Configures cache operation to do before launching '
                           +'Chrome. (Default is clear).')
   parser.add_argument('--wpr-archive', default=None, type=str,
                       help='Web page replay archive to load job\'s urls from.')
   parser.add_argument('--wpr-record', default=False, action='store_true',
                       help='Record web page replay archive.')
+  parser.add_argument('--disable-wpr-script-injection', default=False,
+                      action='store_true',
+                      help='Disable WPR default script injection such as ' +
+                          'overriding javascript\'s Math.random() and Date() ' +
+                          'with deterministic implementations.')
   args = parser.parse_args()
 
   if not os.path.isdir(args.output):
     try:
       os.makedirs(args.output)
     except OSError:
       logging.error('Cannot create directory for results: %s' % args.output)
       raise
   else:
     _CleanPreviousTraces(args.output)
 
   job_urls = _ReadUrlsFromJobDescription(args.job)
   device = device_utils.DeviceUtils.HealthyDevices()[0]
   local_cache_archive_path = os.path.join(args.output, 'cache.zip')
   local_cache_directory_path = None
 
   if args.cache_op == 'push':
     assert os.path.isfile(local_cache_archive_path)
     local_cache_directory_path = tempfile.mkdtemp(suffix='.cache')
     _UnzipDirectoryContent(local_cache_archive_path, local_cache_directory_path)
 
-  with device_setup.WprHost(device,
-                            args.wpr_archive,
-                            args.wpr_record) as additional_flags:
+  with device_setup.WprHost(device, args.wpr_archive, args.wpr_record,
+      args.disable_wpr_script_injection) as additional_flags:
     pages_loaded = 0
     for _ in xrange(args.repeat):
       for url in job_urls:
         if args.cache_op == 'push':
           device.KillAll(_CHROME_PACKAGE, quiet=True)
           _PushBrowserCache(device, local_cache_directory_path)
         with device_setup.DeviceConnection(
             device=device,
             additional_flags=additional_flags) as connection:
           if (pages_loaded == 0 and args.cache_op == 'save' or
@@ skipping 19 matching lines @@
     device.KillAll(_CHROME_PACKAGE, quiet=True)
     time.sleep(_TIME_TO_DEVICE_IDLE_SECONDS)
 
     cache_directory_path = _PullBrowserCache(device)
     _ZipDirectoryContent(cache_directory_path, local_cache_archive_path)
     shutil.rmtree(cache_directory_path)
 
 
 if __name__ == '__main__':
   sys.exit(main())