Add ThreadPool.abort() to stop processing early.

tools/isolateserver_load_test.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 """Uploads a ton of stuff to isolateserver to test its handling.
 
 Generates an histogram with the latencies to download a just uploaded file.
 
 Note that it only looks at uploading and downloading and do not test
@@ skipping 39 matching lines @@
     data += random.choice(self.pool)[:rest]
     return data
 
 
 class Progress(threading_utils.Progress):
   def __init__(self, *args, **kwargs):
     super(Progress, self).__init__(*args, **kwargs)
     self.total = 0
 
   def increment_index(self, name):
-    self.update_item(name, index=True)
+    self.update_item(name, index=1)
 
   def increment_count(self):
-    self.update_item('', size=True)
+    self.update_item('', size=1)
 
   def gen_line(self, name):
     """Generates the line to be printed.
 
     |name| is actually the item size.
     """
     if name:
       self.total += name
       name = graph.to_units(name)
 
@@ skipping 182 matching lines @@
   print('')
   print_results(results, options.columns, options.buckets)
   if options.dump:
     with open(options.dump, 'w') as f:
       json.dump(results, f, separators=(',',':'))
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())