Revert of content: Fix single process support for native GpuMemoryBuffers.

Revert of content: Fix single process support for native GpuMemoryBuffers. (patchset #1 id:1 of https://codereview.chromium.org/1221473003/)

Reason for revert:
XP_tests started failing with "missing shard" exceptions. Suspect this cl.

https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/38438

Original issue's description:
> content: Fix single process support for native GpuMemoryBuffers.
>
> Also add the startup message filter for CreateGpuMemoryBuffer
> messages in single process mode.
>
> BUG=497559, 504121
>
> Committed: https://crrev.com/29ec87df6cef29b9f28dd21d385f16ce99df9ce3
> Cr-Commit-Position: refs/heads/master@{#336495}

TBR=piman@chromium.org,reveman@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=497559, 504121
Committed: https://crrev.com/1cf221f6cebc8850220100c24d00a18ad54bfe8d
Cr-Commit-Position: refs/heads/master@{#336531}

[kcarattini, 2015-06-29 05:45:33]

Created Revert of content: Fix single process support for native
GpuMemoryBuffers.

[commit-bot: I haz the power, 2015-06-29 05:45:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1210073003/1

[commit-bot: I haz the power, 2015-06-29 05:45:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-29 05:46:44]

Patchset 1 (id:??) landed as
https://crrev.com/1cf221f6cebc8850220100c24d00a18ad54bfe8d
Cr-Commit-Position: refs/heads/master@{#336531}

[reveman, 2015-06-29 15:40:44]

On 2015/06/29 at 05:46:44, commit-bot wrote:
> Patchset 1 (id:??) landed as
https://crrev.com/1cf221f6cebc8850220100c24d00a18ad54bfe8d
> Cr-Commit-Position: refs/heads/master@{#336531}

did this fix the problem?

[grt (UTC plus 2), 2015-06-29 18:13:04]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1218783003/ by grt@chromium.org.

The reason for reverting is: Reverting the revert since this wasn't the problem
after all..