The Windows vs POSIX implementations of shared-memory config already differ; we should be able to make them more uniform by passing the kFieldTrialDescriptor as part of the serialized SharedMemoryHandle switch value (even though that is strictly unnecessary).

For Fuchsia we will need to either tie creation of the serialized id of the handle to LaunchProcess, or replicate something like the POSIX GlobalDescriptor helper (possibly both).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8cebdda8cb18dc90a4b5546e450936179417613f

commit 8cebdda8cb18dc90a4b5546e450936179417613f
Author: James Robinson <jamesr@google.com>
Date: Tue Oct 24 20:30:59 2017

[fuchsia] Set kUseSharedMemoryForFieldTrials to false on Fuchsia

Plumbing of the shared memory handle value to the child process is not
yet implemented for Fuchsia.

Bug: 752368
Change-Id: I23699d429ec145bdf8c64942062bdb3316f1b7b8
Reviewed-on: https://chromium-review.googlesource.com/734643
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: James Robinson <jamesr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511249}
[modify] https://crrev.com/8cebdda8cb18dc90a4b5546e450936179417613f/base/metrics/field_trial.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9975df1877a5cdfebf5787aa6517d7c9338c8ba7

commit 9975df1877a5cdfebf5787aa6517d7c9338c8ba7
Author: Scott Graham <scottmg@chromium.org>
Date: Wed Oct 25 22:33:31 2017

fuchsia: disable FieldTrialListTest.ClearParamsFromSharedMemory in base_unittests

TBR: jamesr@chromium.org
Bug: 752368
Change-Id: I90842639f44bef470d40d944c3c692638587e176
Reviewed-on: https://chromium-review.googlesource.com/738629
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: James Robinson <jamesr@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511620}
[modify] https://crrev.com/9975df1877a5cdfebf5787aa6517d7c9338c8ba7/testing/buildbot/filters/fuchsia.base_unittests.filter

 Issue 810222  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c887cf2a868e141eb77fc687bcf07ec9f0b8f7eb

commit c887cf2a868e141eb77fc687bcf07ec9f0b8f7eb
Author: Wez <wez@chromium.org>
Date: Thu Feb 08 03:15:44 2018

Filter FieldTrialListTest.TestCopyFieldTrialStateToFlags under Fuchsia.

This test assumes the ability to transfer field-trial state using
shared-memory, and fails otherwise.

Bug:  810222 , 752368
Change-Id: I8dcc320e782fbd46281eab38d2f5a71e68999471
Reviewed-on: https://chromium-review.googlesource.com/906981
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535284}
[modify] https://crrev.com/c887cf2a868e141eb77fc687bcf07ec9f0b8f7eb/testing/buildbot/filters/fuchsia.base_unittests.filter

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/62c715550ee24d8b24ef1069819719c2d3abafb0

commit 62c715550ee24d8b24ef1069819719c2d3abafb0
Author: Fabrice de Gans-Riberi <fdegans@chromium.org>
Date: Mon Jun 18 19:36:35 2018

Filter out all remaining base tests on Fuchsia.

This removes all the remaining disabled tests in the filter file for
base tests on Fuchsia and instead filters each of them individually.

Bug: 738275, 752368, 753490, 810077, 811881, 851734, 851747, 851759, 851760
Change-Id: I375954138d09ebacc05b2ad37afe1e09901e52e2
Reviewed-on: https://chromium-review.googlesource.com/1096483
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568112}
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/allocator/partition_allocator/address_space_randomization_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/files/file_proxy_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/files/file_util_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/message_loop/message_loop_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/metrics/field_trial_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/observer_list_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/process/process_util_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/synchronization/condition_variable_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/sys_info_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/threading/platform_thread_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/trace_event/process_memory_dump_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/base/trace_event/trace_category_unittest.cc
[modify] https://crrev.com/62c715550ee24d8b24ef1069819719c2d3abafb0/testing/buildbot/filters/fuchsia.base_unittests.filter