The failures on 2016-08-09 are all on linux_chromium_chromeos_rel_ng due to a failing DCHECK_EQ(rv, 0) << ". " << strerror(rv) in LockImpl::Lock(), in lock_impl.posix.cc.

LockImpl::Lock() was touched by bcwhite@chromium.org in https://chromium.googlesource.com/chromium/src/+/5d3470e5a33aaad936e171bee625b6b978ee3c34 about 7 hours before the first flake, and there are a few hours between each flake, so it's a fairly likely culprit. I will revert it and am assigning this to the CL author.

Example backtrace:

[13450:13471:0809/031919:FATAL:lock_impl_posix.cc(65)] Check failed: rv == 0 (22 vs. 0). Invalid argument
#0 0x000002ed086e base::debug::StackTrace::StackTrace()
#1 0x000002ee5b6a logging::LogMessage::~LogMessage()
#2 0x000002f1f16a base::internal::LockImpl::Lock()
#3 0x000001c66aa0 content::HostZoomMapImpl::GetZoomLevelForView()
#4 0x000001c37fc1 content::RenderFrameMessageFilter::GetHostZoomLevel()
#5 0x000001fce88a content::mojom::RenderFrameMessageFilterStub::AcceptWithResponder()
#6 0x000004526ebf mojo::InterfaceEndpointClient::HandleValidatedMessage()
#7 0x000001fcecea content::mojom::RenderFrameMessageFilterRequestValidator::Accept()
#8 0x000004527bfa mojo::InterfaceEndpointClient::HandleIncomingMessage()
#9 0x000004518fb7 IPC::(anonymous namespace)::ChannelAssociatedGroupController::Accept()
#10 0x000004529785 mojo::MessageHeaderValidator::Accept()
#11 0x000004525482 mojo::Connector::ReadSingleMessage()
#12 0x000004525924 mojo::Connector::OnHandleReadyInternal()
#13 0x0000019e1d9b mojo::Watcher::OnHandleReady()
#14 0x000002f59b86 base::debug::TaskAnnotator::RunTask()
#15 0x000002eed085 base::MessageLoop::RunTask()
#16 0x000002eed378 base::MessageLoop::DeferOrRunPendingTask()
#17 0x000002eed6bb base::MessageLoop::DoWork()
#18 0x000002eeffa9 base::MessagePumpLibevent::Run()
#19 0x000002eecbcd base::MessageLoop::RunHandler()
#20 0x000002f0e220 base::RunLoop::Run()
#21 0x000002f300ae base::Thread::Run()
#22 0x000001b49ba5 content::BrowserThreadImpl::IOThreadRun()
#23 0x000001b49d38 content::BrowserThreadImpl::Run()
#24 0x000002f30400 base::Thread::ThreadMain()
#25 0x000002f2b5f5 base::(anonymous namespace)::ThreadFunc()
#26 0x7f73f5ddee9a start_thread
#27 0x7f73f156036d clone

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b3655198b775c54da3170736a62f48b0f7964fb9

commit b3655198b775c54da3170736a62f48b0f7964fb9
Author: Philip Jägenstedt <foolip@chromium.org>
Date: Tue Aug 09 11:49:01 2016

Revert "Track thread activities in order to diagnose hangs."

This reverts commit 5d3470e5a33aaad936e171bee625b6b978ee3c34.

This is the likely cause of
MultiProfileFileManagerBrowserTest.PRE_BasicDrive becoming flaky.

(Manual revert, CL was too big for revert button.)

BUG= 635832 ,620813
TBR=bcwhite@chromium.org

Review URL: https://codereview.chromium.org/2221343002 .

Cr-Commit-Position: refs/heads/master@{#410635}

[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/BUILD.gn
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/base.gyp
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/base.gypi
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/OWNERS
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_analyzer.cc
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_analyzer.h
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_analyzer_unittest.cc
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_tracker.cc
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_tracker.h
[delete] https://crrev.com/5bc62a8764ac6b005c185526f58ed82b39413268/base/debug/activity_tracker_unittest.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/debug/task_annotator.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/process/process_posix.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/process/process_win.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/synchronization/lock_impl_posix.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/synchronization/lock_impl_win.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/synchronization/waitable_event_posix.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/synchronization/waitable_event_win.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/threading/platform_thread_posix.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/base/threading/platform_thread_win.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/chrome/browser/chrome_browser_field_trials_desktop.cc
[modify] https://crrev.com/b3655198b775c54da3170736a62f48b0f7964fb9/tools/metrics/histograms/histograms.xml

The failure is an invalid argument to Lock() so my change shouldn't be the cause unless it is corrupting the stack somehow.  Manual inspection didn't reveal any way that would happen.

The revert landed at 11:53 UTC and another flake occurred at 13:57 UTC so it doesn't appear to be my change.

Stack trace shows a call to content::HostZoomMapImpl::GetZoomLevelForView() which was added in https://codereview.chromium.org/2211713002

Scott, over to you...

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c

commit 3ea157196bfdddd8dc3c82b2e994e4a932b8d46c
Author: scottmg <scottmg@chromium.org>
Date: Tue Aug 09 16:46:41 2016

Revert of Remove dependency of c/b/loader on c/b/host_zoom_map_impl.h (patchset #9 id:180001 of https://codereview.chromium.org/2211713002/ )

Reason for revert:
Looks like there's a race during initialization on chromeos https://bugs.chromium.org/p/chromium/issues/detail?id=635832#c3

Original issue's description:
> Remove dependency of c/b/loader on c/b/host_zoom_map_impl.h
>
> Contrary to previous attempt at:
> https://chromium.googlesource.com/chromium/src.git/+/68c6f2ce16d9807b5cb82679099c82c40f39e911
>
> RenderFrameMessageFilter is on the IO thread, and is a BrowserAssociatedInterface, so will maintain the ordering of the resource request and the zoom level request. See also https://codereview.chromium.org/2167513003.
>
> BUG= 609607 
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
>
> Committed: https://crrev.com/d4423d511f18f4b0d2e94cf17bf6043bee449c55
> Cr-Commit-Position: refs/heads/master@{#410417}

TBR=jam@chromium.org,tsepez@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 609607 ,  635832 

Review-Url: https://codereview.chromium.org/2222403002
Cr-Commit-Position: refs/heads/master@{#410705}

[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/build/android/pylib/gtest/filter/content_browsertests_disabled
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/frame_host/render_frame_message_filter.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/frame_host/render_frame_message_filter.h
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/host_zoom_map_impl.h
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/DEPS
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/async_resource_handler.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/async_resource_handler_unittest.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/async_revalidation_manager_unittest.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/resource_dispatcher_host_unittest.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/resource_message_filter.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/loader/resource_message_filter.h
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/browser/renderer_host/render_process_host_impl.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/common/render_frame_message_filter.mojom
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/common/view_messages.h
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_frame_impl.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_frame_impl.h
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_frame_impl_browsertest.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_view_browsertest.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_view_impl.cc
[modify] https://crrev.com/3ea157196bfdddd8dc3c82b2e994e4a932b8d46c/content/renderer/render_view_impl.h

 Issue 636266  has been merged into this issue.