"In particular this can become a real issue when the total output is larger than 16Mb, which affects the task."

Example affected task: https://chromium-swarm.appspot.com/task?id=36921085af83a110&refresh=0&request_detail=true&wide_logs=1

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/luci/luci-py.git/+/adaf48426621c897d1bd094cd73906d7bfab3d50

commit adaf48426621c897d1bd094cd73906d7bfab3d50
Author: Tim 'mithro' Ansell <tansell@chromium.org>
Date: Thu Sep 07 23:41:56 2017

swarming.py: Add --task-output-stdout option

Enables the ability to control where the stdout of a task ends up going.
The options are;

 * Don't download / get at all.
 * Only output to the json summary file.
 * Only output to the console.
 * Continue to output in all of the above (default).

At the moment when using swarming on the build bots we end up with;
 - stdout in swarming
 - stdout in the collect_task output
 - stdout inside the summary.json file

For Layout Tests where the stdout is *long* this makes recipes take
significant time in just parsing the summary.json output.

BUG= 731095 

Change-Id: I0fa7228a5be21820b3089306f6e9c8646983159c
Reviewed-on: https://chromium-review.googlesource.com/654020
Reviewed-by: Tim 'mithro' Ansell <tansell@chromium.org>
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Commit-Queue: Tim 'mithro' Ansell <tansell@chromium.org>

[modify] https://crrev.com/adaf48426621c897d1bd094cd73906d7bfab3d50/client/swarming.py
[modify] https://crrev.com/adaf48426621c897d1bd094cd73906d7bfab3d50/client/tests/swarming_test.py
[modify] https://crrev.com/adaf48426621c897d1bd094cd73906d7bfab3d50/client/tools/swarming_load_test_client.py

With  https://chromium-review.googlesource.com/654020 we now have a way to do this;

 swarming.py --task-output-stdout=(console|json|none|both)

I'm planning on deploying this feature for Layout Tests on swarming soon.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/519e4311ba5a076a7102b48e9efdbdcda2ed06e1

commit 519e4311ba5a076a7102b48e9efdbdcda2ed06e1
Author: Tim 'mithro' Ansell <tansell@chromium.org>
Date: Fri Sep 08 02:26:19 2017

Roll src/tools/swarming_client/ 72b6a2dc6..5e8001d9a (7 commits)

https://chromium.googlesource.com/infra/luci/client-py.git/+log/72b6a2dc6046..5e8001d9a710

$ git log 72b6a2dc6..5e8001d9a --date=short --no-merges --format='%ad %ae %s'
2017-09-08 tansell swarming.py: Add --task-output-stdout option
2017-09-07 justincohen tools/run_on_bots: Enable running a task in batches.
2017-08-31 tansell Removing arfile.
2017-08-31 tansell tools/run_on_bots: Enable giving a hash instead of script.
2017-08-30 aludwin Implement task updates in gRPC proxy
2017-08-29 justincohen Add support for no bots found in run_on_bots.py
2017-08-17 maruel More improvements to run_on_bots.py

Created with:
  roll-dep src/tools/swarming_client

R=maruel@chromium.org,dpranke@chromium.org
BUG= 731095 

Change-Id: I0d53fd7f17d3b24cc37a24f230a85c7b5b3797da
Reviewed-on: https://chromium-review.googlesource.com/656401
Commit-Queue: Tim 'mithro' Ansell <tansell@chromium.org>
Commit-Queue: Marc-Antoine Ruel <maruel@chromium.org>
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#500489}
[modify] https://crrev.com/519e4311ba5a076a7102b48e9efdbdcda2ed06e1/DEPS