The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/e24c7a21f76557bc8d1434906393b2838c714500

commit e24c7a21f76557bc8d1434906393b2838c714500
Author: Brandon Mayer <bmayer@chromium.org>
Date: Sat Aug 12 01:07:04 2017

debugd: Added log size query to debugd interface.

Example:
>> dbus-send --type=method_call --system --print-reply  \
  --dest=org.chromium.debugd /org/chromium/debugd org.chromium.debugd.GetLog \
  string:system_log_stats

Output:
   string "BLOCK_SIZE=1024
3996	  /var/log/messages
1284	  /var/log/atrus.log
1028	  /var/log/displaylink/DisplayLinkManager.old.log
676	  /var/log/displaylink/DisplayLinkManager.log
532	  /var/log/net.log
220	  /var/log/tlsdate.log
220	  /var/log/secure
112	  /var/log/vmlog/vmlog.20170809-135843
...

BUG= chromium:752999 
TEST=Built and deployed to device and call log tool via dbus-send.

Change-Id: Id3da84f063d5555406ce6a8fb20d5bac7bdb560a
Reviewed-on: https://chromium-review.googlesource.com/604247
Commit-Ready: Brandon Mayer <bmayer@chromium.org>
Tested-by: Brandon Mayer <bmayer@chromium.org>
Reviewed-by: Simon Que <sque@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[modify] https://crrev.com/e24c7a21f76557bc8d1434906393b2838c714500/debugd/src/log_tool.cc