commit 6836c0d55acc3e3b6730c042d01b1ba7f2bc886c
author Gabriel Charette <gab@chromium.org> Mon Jan 11 17:40:26 2021
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jan 11 17:40:26 2021
tree 94b3398872afeb078a88d2cc2acb40f5f9237914
parent fbddb1797e6935d6bf7c0a248c61fbee66a264f6

Reland "[base] Fix trace events and blocking types when blocked on modal dialogs"

This is a reland of 2ecb8d17bc59b94113efae9607c82ab976d541f4

Revert reason seemed unrelated, but FindIt is strangely convinced.
The TSAN issue was fixed in
https://chromium-review.googlesource.com/c/chromium/src/+/2618393
nonetheless.

Original change's description:
> [base] Fix trace events and blocking types when blocked on modal dialogs
>
> Sheriff notes: This is expected to artificially reduce IOJank* metrics.
>
> Modal dialogs launched via GetAppOutputInternal in launch_posix.cc
> are guaranteed to block and thus should use WILL_BLOCK semantics
> (as opposed to MAY_BLOCK like it did).
>
> However, Process::WaitForExit can't use WILL_BLOCK semantics because
> of an existing workaround for TestLauncher to not use
> ScopedBlockingCallWithBaseSyncPrimitives when waiting on processes or
> TestLauncher ends up creating or TestLauncher ends up flooding
> the pool to 256 workers regardless of --test-launcher-jobs
> (it posts each test as a task right off the bat and expects the
> pool to cap the parallelism...).
>
> The best solution to get proper tracing and thread restrictions
> right is thus to add custom trace events and keep assertions
> that waiting is allowed when launching the process.
>
> Each platform was doing something slightly different here, this
> CL brings all platforms inline with annotations that are visible
> in tracing but ignored by IOJank metrics.
>
> Example broken trace showing up in IOJank slow reports on Linux:
> https://goto.google.com/btbzu (SS: https://snipboard.io/7sDO1r.jpg)
>
> R=fdoray@chromium.org
>
> Bug: 1064645, 1144161, 899897
> Change-Id: Id087f91df8c2201ca10db5438456c638f9b791e9
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2233299
> Commit-Queue: Gabriel Charette <gab@chromium.org>
> Reviewed-by: Wez <wez@chromium.org>
> Reviewed-by: François Doray <fdoray@chromium.org>
> Reviewed-by: Joe Downing <joedow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#837874}

TBR=fdoray@chromium.org,wez@chromium.org
(identical as before)

Bug: 1064645
Bug: 1144161
Bug: 899897
Change-Id: I8f4161d9c614db1670648b54d5949fdfe49a6b02
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2621912
Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842081}