The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/01602d5648048dabb5dbccd96eade4a7fe1e4e32

commit 01602d5648048dabb5dbccd96eade4a7fe1e4e32
Author: Jonathan Metzman <metzman@chromium.org>
Date: Thu Oct 04 18:12:38 2018

[libFuzzer][Windows] Enable optimize_for_fuzzing

Bug:  890639 
Change-Id: Icb2be76982816119a30925fa92121445b5ca5141
Reviewed-on: https://chromium-review.googlesource.com/c/1253023
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596757}
[modify] https://crrev.com/01602d5648048dabb5dbccd96eade4a7fe1e4e32/build/config/compiler/BUILD.gn

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f71734735c658bb06996ed086e970ff6b671a293

commit f71734735c658bb06996ed086e970ff6b671a293
Author: Jonathan Metzman <metzman@chromium.org>
Date: Fri Oct 05 17:33:58 2018

Revert "[libFuzzer][Windows] Enable optimize_for_fuzzing"

This reverts commit 01602d5648048dabb5dbccd96eade4a7fe1e4e32.

Reason for revert: /O1 is not the clang-cl equivalent of -O1 

Original change's description:
> [libFuzzer][Windows] Enable optimize_for_fuzzing
> 
> Bug:  890639 
> Change-Id: Icb2be76982816119a30925fa92121445b5ca5141
> Reviewed-on: https://chromium-review.googlesource.com/c/1253023
> Reviewed-by: Max Moroz <mmoroz@chromium.org>
> Reviewed-by: Scott Graham <scottmg@chromium.org>
> Commit-Queue: Jonathan Metzman <metzman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#596757}

TBR=thakis@chromium.org,scottmg@chromium.org,mmoroz@chromium.org,metzman@chromium.org

Change-Id: Ic407400440a3e6c58940b77708ab5334736242bb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  890639 
Reviewed-on: https://chromium-review.googlesource.com/c/1264680
Reviewed-by: Jonathan Metzman <metzman@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597184}
[modify] https://crrev.com/f71734735c658bb06996ed086e970ff6b671a293/build/config/compiler/BUILD.gn

I'm less convinced that optimize_for_fuzzing is actually useful on Linux. In any case, it seems good for shaking out bugs and increasing coverage of program behavior for different builds to use different optimization flags.