Fixed in the following patchset:
https://codereview.chromium.org/2648263005/

Run software reporter's experimental engine on all architectures

Allows using the experimental engine of the software reporter component
if ExperimentalSwReporterEngineOnAllArchitectures feature is enabled
regardless of the system's bitness. 

Is this change applicable to any other OSes or just windows?

Just Windows.

Your change meets the bar and is auto-approved for M57. Please go ahead and merge the CL to branch 2987 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Please merge  your change to M57 branch 2987 ASAP.If merge happens today before 5:00 PM PT, then we can take it for tomorrow's last M57 Dev release. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/45dcaa149c4eea6fb0bab9467f3e4e1506714254

commit 45dcaa149c4eea6fb0bab9467f3e4e1506714254
Author: Marc-Antoine Courteau <macourteau@chromium.org>
Date: Mon Jan 30 21:18:03 2017

Run software reporter's experimental engine on all architectures

Allows using the experimental engine of the software reporter component
if ExperimentalSwReporterEngineOnAllArchitectures feature is enabled
regardless of the system's bitness.

BUG= 685705 

Review-Url: https://codereview.chromium.org/2648263005
Cr-Commit-Position: refs/heads/master@{#446127}
(cherry picked from commit 8f32a8905fcbc1c904ac48add7e66696cba2ddc0)

Review-Url: https://codereview.chromium.org/2660993003 .
Cr-Commit-Position: refs/branch-heads/2987@{#187}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/45dcaa149c4eea6fb0bab9467f3e4e1506714254/chrome/browser/component_updater/sw_reporter_installer_win.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/45dcaa149c4eea6fb0bab9467f3e4e1506714254

commit 45dcaa149c4eea6fb0bab9467f3e4e1506714254
Author: Marc-Antoine Courteau <macourteau@chromium.org>
Date: Mon Jan 30 21:18:03 2017

Run software reporter's experimental engine on all architectures

Allows using the experimental engine of the software reporter component
if ExperimentalSwReporterEngineOnAllArchitectures feature is enabled
regardless of the system's bitness.

BUG= 685705 

Review-Url: https://codereview.chromium.org/2648263005
Cr-Commit-Position: refs/heads/master@{#446127}
(cherry picked from commit 8f32a8905fcbc1c904ac48add7e66696cba2ddc0)

Review-Url: https://codereview.chromium.org/2660993003 .
Cr-Commit-Position: refs/branch-heads/2987@{#187}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/45dcaa149c4eea6fb0bab9467f3e4e1506714254/chrome/browser/component_updater/sw_reporter_installer_win.cc