Set tracing categories explicitly in Clovis and Sandwich

tools/android/loading/queuing_lens.py

 # 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.
 
 """Lens for resource load queuing.
 
 When executed as a script, takes a loading trace and prints queuing information
 for each request.
 """
 
 import collections
 import itertools
 import logging
 
-import tracing
+import clovis_constants
 
 
 class QueuingLens(object):
   """Attaches queuing related trace events to request objects."""
-  QUEUING_CATEGORY = tracing.QUEUING_CATEGORY
+  QUEUING_CATEGORY = clovis_constants.QUEUING_CATEGORY

[blundell, 2016/06/06 16:06:38]

nit: maybe this should still be defined in tracing.py since the name of the
category isn't itself specific to Clovis?

[gabadie, 2016/06/06 16:17:30]

Curious: why would only this category be defined in tracing? Does it have any
particularity compared to the other ones?

Might not be consistent unless we defines all the other as well...

[pasko, 2016/06/06 17:30:52]

I am concerned with clovis_constants.py and tracing.py depending on each other.
Circular dependencies are harder to understand and manage.

We can make tracing_constants.py and have there:
QUEUING_CATEGORY
CLOVIS_DEFAULT_CATEGORIES

other suggestions are welcome, beyond circular dependencies I do not have clear
naming preferences yet.

[gabadie, 2016/06/06 17:37:10]

To me it just looks fine as is.

   ASYNC_NAME = 'ScheduledResourceRequest'
   READY_NAME = 'ScheduledResourceRequest.Ready'
   SET_PRIORITY_NAME = 'ScheduledResourceRequest.SetPriority'
   QUEUING_NAMES = set([ASYNC_NAME,
                        READY_NAME,
                        SET_PRIORITY_NAME])
 
   IN_FLIGHT_NAME = 'ResourceScheduler::Client.InFlightRequests'
   SHOULD_START_NAME = 'ResourceScheduler::Client::ShouldStartRequestInfo'
 
@@ skipping 121 matching lines @@
         fp=rq.fingerprint,
         ts=mkmsec(info.start_msec), te=mkmsec(info.end_msec),
         rs=mkmsec(rq.start_msec), re=mkmsec(rq.end_msec),
         ids=info.source_ids, url=rq.url)
     for blocking_request in info.blocking:
       print '  {} {}'.format(blocking_request.fingerprint, blocking_request.url)
 
 if __name__ == '__main__':
   import sys
   _Main(sys.argv[1])