content: Fix single process support for native GpuMemoryBuffers.

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}

[reveman, 2015-06-26 20:10:59]

reveman@chromium.org changed reviewers:
+ piman@chromium.org

[piman, 2015-06-27 01:32:36]

lgtm

[reveman, 2015-06-27 13:37:14]

The CQ bit was checked by reveman@chromium.org

[commit-bot: I haz the power, 2015-06-27 13:37:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1221473003/1

[commit-bot: I haz the power, 2015-06-27 13:48:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-27 13:49:36]

Patchset 1 (id:??) landed as
https://crrev.com/29ec87df6cef29b9f28dd21d385f16ce99df9ce3
Cr-Commit-Position: refs/heads/master@{#336495}

[kcarattini, 2015-06-29 05:45:32]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1210073003/ by kcarattini@chromium.org.

The reason for reverting is: XP_tests started failing with "missing shard"
exceptions. Suspect this cl.

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

[grt (UTC plus 2), 2015-06-29 13:52:46]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1217853002/ by grt@chromium.org.

The reason for reverting is: Speculative revert to see if this is what broke XP
Tests (1)..