GitLab

This reverts commit 4363f493.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 816834 as the
culprit for failures in the build cycles as shown on:
https://analysis.chromium.org/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtLzQzNjNmNDkzNDNkZjgyZDNiOWJiMmZiYmI1NWJjNDQ0OGVhYmZmNGEM

Sample Failed Build: https://ci.chromium.org/b/8866507600045542768

Sample Failed Step: compile

Original change's description:
> [PartitionAlloc] Zero on free.
> 
> This CL 'zaps' (`memset`s) the allocated region on free. This may
> help detect some instances of UAF, causing them to crash (with
> nullptr deref).
> 
> Rather than doing so on every free, we zap probabilistically to
> reduce the performance impact.
> 
> If the perf bots show an unacceptable regression, we'll revert this.
> But, it might be acceptable.
> 
> Bug: 1005070, 1013329, 1013326, 1013324
> Change-Id: Ia36ee17625290646216985dd6fdffabfa84a9ba2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1873272
> Commit-Queue: Chris Palmer <palmer@chromium.org>
> Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#816834}


Change-Id: I3ebcc5179fa0830faa5c9df8dae63a562cdb0b1b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1005070, 1013329, 1013326, 1013324
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2469840
Cr-Commit-Position: refs/heads/master@{#816836}