Revert of [Discardable Shared Memory] Adding Windows support. (patchset #5 id:80001 of https://codereview.chromium.org/1427163003/ )

Reason for revert:
Speculative revert: this may cause regression to smoothness.tough_canvas_cases

BUG=555225

Original issue's description:
> [Discardable Shared Memory] Adding Windows support.
>
> 1) Purge(): Now doing VirtualFree MEM_DECOMMIT back to XP during a purge.
> This releases the physical storage, either in memory or in the paging file on disk.
> Pages remain RESERVED.  NOTE: this is the best that can be done immediately
> from the browser, until the child/renderer notices the purge and releases its own
> handles.
>
> 2) Lock/Unlock() pinning: For >= Win8, we have access to MEM_RESET_UNDO support.
> On Unlock(), we now MEM_RESET.  On Lock(), we MEM_RESET_UNDO.
> This mimics the existing Ashmem support on Android.
> (See bug ticket for why OfferVirtualMemory/ReclaimVirtualMemory is not being used.)
>
> BUG=180334
> R=reveman@chromium.org,jschuh@chromium.org
>
> Committed: https://crrev.com/498c30ec10c16ba90cd425836c5a92ac0d685c36
> Cr-Commit-Position: refs/heads/master@{#358466}

TBR=reveman@chromium.org,brucedawson@chromium.org,jschuh@chromium.org,danakj@chromium.org,thestig@chromium.org,pennymac@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=180334

Review URL: https://codereview.chromium.org/1473733005

Cr-Commit-Position: refs/heads/master@{#361748}

0 files changed, 0 insertions, 0 deletions