I think there should now be a link at the bottom of a test's output that will take you to the logcats. It should look something like "https://luci-logdog.appspot.com/v/?s=chromium%2Fandroid%2Fswarming%2Flogcats%..."

err, still not sure where that link is.. where is that link on this run?
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/262568

Say you wanted the logcats for components_unittests, you'd click the stdout link underneath that test (step #56), scroll to the bottom, and there's this line of text:

C  733.050s Main  Logcat: https://luci-logdog.appspot.com/v/?s=chromium%2Fandroid%2Fswarming%2Flogcats%2F353f0a7c08dd1311%2F%2B%2Funified_logcats

cool, so looks like it's very close to actually surfacing that link directly in the buildbot page. but this intermediate state is so much worse. can we make sure these changes are communicated with developers?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9ae14459caaa7f3b049b3d44be2c209890773213

commit 9ae14459caaa7f3b049b3d44be2c209890773213
Author: hzl <hzl@google.com>
Date: Tue Apr 04 23:38:02 2017

Save the logcat file in isolated directory.

Previously we store the logcat into a temporary directory, which will be
deleted shortly. That means logcat will not be viewable in the isolated
directory.

In this cl, we are storing the logcat in the isolated directory, for
later easier view. This is a temporary fix before result details is
enabled.

BUG= 707387 

Review-Url: https://codereview.chromium.org/2797773003
Cr-Commit-Position: refs/heads/master@{#461898}

[modify] https://crrev.com/9ae14459caaa7f3b049b3d44be2c209890773213/build/android/test_wrapper/logdog_wrapper.py
[modify] https://crrev.com/9ae14459caaa7f3b049b3d44be2c209890773213/tools/mb/mb.py

Thank bo so much for taking the time to report this issue. I believe the bug is fixed now and logcat is visible in isolated out now.