fwiw, I guessed at that in #c21 there, but wasn't able to cause a problem by making the crash dump take very long. It seemed to wait as expected.

The only time I reproduced telemetry mistakenly thinking the tab was gone was by shutting down the browser mid-test.

As far as I can tell, at least one bug in the Perf bots' setup is that they build the chromium_builder_perf target (see any recent build on https://build.chromium.org/p/chromium.perf/builders/Win%20x64%20Builder ) , and this doesn't include a dependency on crashpad_database_util.exe, or any of the other important dependencies like the copy_cdb_to_output step in src/tools/perf/chrome_telemetry_build/BUILD.gn. I'm going to add logging to Telemetry's desktop_browser_backend to narrow down why it didn't find the minidump. On my machine, adding a DCHECK early on in renderer startup, if crashpad_database_util was missing then the symptom on the Perf bots happened. Once that target was built, the minidumps started getting found and symbolized.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d078c69020beaab39b72bba3d6a1a45a2386cd12

commit d078c69020beaab39b72bba3d6a1a45a2386cd12
Author: catapult-deps-roller <catapult-deps-roller@chromium.org>
Date: Fri May 27 06:37:56 2016

Roll src/third_party/catapult/ baa2999e8..aa8636016 (1 commit).

https://chromium.googlesource.com/external/github.com/catapult-project/catapult.git/+log/baa2999e8462..aa8636016c8a

$ git log baa2999e8..aa8636016 --date=short --no-merges --format='%ad %ae %s'

BUG= 615180 

TBR=catapult-sheriff@chromium.org

Review-Url: https://codereview.chromium.org/2015143003
Cr-Commit-Position: refs/heads/master@{#396408}

[modify] https://crrev.com/d078c69020beaab39b72bba3d6a1a45a2386cd12/DEPS

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1e58e78ecce28f5891912c000c5d2520e4f5b09d

commit 1e58e78ecce28f5891912c000c5d2520e4f5b09d
Author: kbr <kbr@chromium.org>
Date: Fri May 27 17:21:19 2016

Refactor dependencies for chromium_builder_perf target.

The perf bots build this target, but don't use isolates and therefore
aren't on the same overall path as the bots which run
telemetry_perf_unittests, where minidump processing is well tested.

Make this target depend on telemetry_chrome_test, and remove redundant
dependencies on chrome and bitmaptools. This should cause the tools
which generate and process minidumps to be properly built.

BUG= 615180 

Review-Url: https://codereview.chromium.org/2019553002
Cr-Commit-Position: refs/heads/master@{#396497}

[modify] https://crrev.com/1e58e78ecce28f5891912c000c5d2520e4f5b09d/BUILD.gn

I think this is fixed. Unfortunately the only way to really test it is to induce a crash on the Perf bots, which obviously isn't desirable. Maybe we could try re-enabling the test from  Issue 615178  briefly and see if a reasonable crash stack is printed.