The failing test has been disabled by this CL:
https://chromium-review.googlesource.com/c/chromium/src/+/1204414

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cf76179da5cd10c03219871b11c417b06af43254

commit cf76179da5cd10c03219871b11c417b06af43254
Author: Samuel Huang <huangs@chromium.org>
Date: Tue Sep 04 17:12:41 2018

[Sheriff] Disable PlatformSharedMemoryRegionTest.MappingProtectionSetCorrectly

The test was recently added in
https://chromium-review.googlesource.com/c/chromium/src/+/1199811

TBR=alexilin@chromium.org,rsesek@chromium.org

Bug:  880414 
Change-Id: Ib8b56036747e42a5cbfdef301f0b2642727e0c7f
Reviewed-on: https://chromium-review.googlesource.com/1204414
Reviewed-by: Samuel Huang <huangs@chromium.org>
Reviewed-by: Alexandr Ilin <alexilin@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588558}
[modify] https://crrev.com/cf76179da5cd10c03219871b11c417b06af43254/base/memory/platform_shared_memory_region_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/41664919f00f8b4d1308cb24c07206e39b66501c

commit 41664919f00f8b4d1308cb24c07206e39b66501c
Author: Alexandr Ilin <alexilin@chromium.org>
Date: Wed Sep 12 14:04:13 2018

base: Reenable PlatformSharedMemoryRegionTest.MappingProtectionSetCorrectly test

The test was checking that a shared memory mapping has are exactly PROT_READ
permissions whereas on some hardware they may be PROT_READ | PROT_EXEC.

From mmap(2) man page:
"It is architecture dependent whether PROT_READ implies PROT_EXEC or not."

Bug:  880414 
Change-Id: I75775f5e2a968014433ebfc6607d1bfdfacb6036
Reviewed-on: https://chromium-review.googlesource.com/1220953
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Alexandr Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590662}
[modify] https://crrev.com/41664919f00f8b4d1308cb24c07206e39b66501c/base/memory/platform_shared_memory_region_unittest.cc