The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5badc11193b7d8143e68215ce7a0e363af1fcae2

commit 5badc11193b7d8143e68215ce7a0e363af1fcae2
Author: Xida Chen <xidachen@chromium.org>
Date: Mon Apr 23 16:50:51 2018

Disable InitialForegroundTabChanged on linux and win

TBR=thestig@chromium.org
NOTRY=true

Bug: 835869
Change-Id: I5a1030e9decb338c2ed8189fbe3500c57a0424c3
Reviewed-on: https://chromium-review.googlesource.com/1023023
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552730}
[modify] https://crrev.com/5badc11193b7d8143e68215ce7a0e363af1fcae2/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8948444018165133184%2F%2B%2Fsteps%2Fbrowser_tests%2F0%2Flogs%2FSessionRestorePageLoadMetricsBrowserTest.InitialForegroundTabChanged%2F0

[ RUN      ] SessionRestorePageLoadMetricsBrowserTest.InitialForegroundTabChanged
Xlib:  extension "RANDR" missing on display ":99".
[21082:21269:0423/081720.146007:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[21082:21082:0423/081720.236884:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
[21082:21082:0423/081720.889922:WARNING:gaia_auth_fetcher.cc(873)] Could not reach Google Accounts servers: errno -11
[21082:21323:0423/081721.889152:WARNING:embedded_test_server.cc(228)] Request not handled. Returning 404: /favicon.ico
[21082:21082:0423/081722.065625:WARNING:gaia_auth_fetcher.cc(873)] Could not reach Google Accounts servers: errno -102
[21082:21082:0423/081725.069035:WARNING:gaia_auth_fetcher.cc(873)] Could not reach Google Accounts servers: errno -102
../../base/test/histogram_tester.cc:186: Failure
Expected equality of these values:
  expected_count
    Which is: 0
  actual_count
    Which is: 1
Histogram "TabManager.Experimental.SessionRestore.ForegroundTab.FirstPaint" does not have the right total number of samples (0). It has (1).
Stack trace:
#0 0x00000b1291c5 StackTraceGetter::CurrentStackTrace()
#1 0x00000b14df7e testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#2 0x00000b14d289 testing::internal::AssertHelper::operator=()
#3 0x00000d615d44 base::HistogramTester::CheckTotalCount()
#4 0x00000d616187 base::HistogramTester::ExpectTotalCount()
#5 0x000008ea66ed SessionRestorePageLoadMetricsBrowserTest::ExpectFirstPaintMetricsTotalCount()

Assigning to fmeawad, who's the owner of TabManager.Experimental.SessionRestore.ForegroundTab.FirstPaint in histograms.xml.