The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/1bbaaa90e415712fab089cedd4a0396601bf9ab3

commit 1bbaaa90e415712fab089cedd4a0396601bf9ab3
Author: Simon <simonhatch@chromium.org>
Date: Tue Nov 28 17:04:46 2017

Add some extra logging to results_dashboard.

We had a bad failure when histograms was enabled last week, extra
logging in here might have helped track down the root cause a bit
quicker. Refactored the code a bit to print out a full traceback
instead of just the exception info. Also added some test coverage for
the histogram upload path.

Bug:  785959 
Change-Id: Id3b165af781f47a538a6aa64cf58208d817f1c07
Reviewed-on: https://chromium-review.googlesource.com/783932
Reviewed-by: Ethan Kuefner <eakuefner@chromium.org>
Reviewed-by: Emily Hanley <eyaich@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Simon Hatch <simonhatch@chromium.org>

[modify] https://crrev.com/1bbaaa90e415712fab089cedd4a0396601bf9ab3/scripts/slave/unittests/results_dashboard_test.py
[modify] https://crrev.com/1bbaaa90e415712fab089cedd4a0396601bf9ab3/scripts/slave/results_dashboard.py

Looks like this was fixed last year.