Revert of gpu: Completely remove GpuProcessHostUIShim.

Revert of gpu: Completely remove GpuProcessHostUIShim. (patchset #4 id:60001 of https://codereview.chromium.org/2820463002/ )

Reason for revert:
This CL break video_VideoDecodeAccelerator and video_VDASanity on all ChromeOS boards.

BUG=715957
Original issue's description:
> gpu: Completely remove GpuProcessHostUIShim.
> 
> The only remaining purpose of GpuProcessHostUIShim was to send messages
> back and forth between GpuProcessHost and the ozone platform. Move that
> relevant code into GpuProcessHost, and remove the ui shim.
> 
> For ozone: Remove GpuPlatformSupportHost::OnChannelEstablished(). It is
> currently needed only for the drm implementation, and is essentially just
> a thread hop from the IO thread to the UI thread. So do that from inside
> the drm implementation, instead of having a public API and requiring the
> gpu host do the thread-hop.
> 
> BUG=709332, 711333
> 
> Review-Url: https://codereview.chromium.org/2820463002
> Cr-Commit-Position: refs/heads/master@{#466351}
> Committed: https://chromium.googlesource.com/chromium/src/+/63c1e2603b28e1fb6a2ca120e793497ed3b37220

TBR=jbauman@chromium.org,dnicoara@chromium.org,rjkroege@chromium.org,jam@chromium.org,sadrul@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=709332, 711333

[kcwu, 2017-04-27 15:10:41]

The CQ bit was checked by kcwu@chromium.org

[kcwu, 2017-04-27 15:10:42]

Created Revert of gpu: Completely remove GpuProcessHostUIShim.

[commit-bot: I haz the power, 2017-04-27 15:11:09]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[sadrul, 2017-04-27 15:13:46]

The CQ bit was unchecked by sadrul@chromium.org

[kcwu, 2017-04-28 06:05:49]

Description was changed from

==========
Revert of gpu: Completely remove GpuProcessHostUIShim. (patchset #4 id:60001 of
https://codereview.chromium.org/2820463002/ )

Reason for revert:
This CL break video_VideoDecodeAccelerator and video_VDASanity on all ChromeOS
boards.

BUG=715957

Original issue's description:
> gpu: Completely remove GpuProcessHostUIShim.
> 
> The only remaining purpose of GpuProcessHostUIShim was to send messages
> back and forth between GpuProcessHost and the ozone platform. Move that
> relevant code into GpuProcessHost, and remove the ui shim.
> 
> For ozone: Remove GpuPlatformSupportHost::OnChannelEstablished(). It is
> currently needed only for the drm implementation, and is essentially just
> a thread hop from the IO thread to the UI thread. So do that from inside
> the drm implementation, instead of having a public API and requiring the
> gpu host do the thread-hop.
> 
> BUG=709332, 711333
> 
> Review-Url: https://codereview.chromium.org/2820463002
> Cr-Commit-Position: refs/heads/master@{#466351}
> Committed:
https://chromium.googlesource.com/chromium/src/+/63c1e2603b28e1fb6a2ca120e793...

TBR=jbauman@chromium.org,dnicoara@chromium.org,rjkroege@chromium.org,jam@chro...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=709332, 711333
==========

to

==========
Revert of gpu: Completely remove GpuProcessHostUIShim. (patchset #4 id:60001 of
https://codereview.chromium.org/2820463002/ )

Reason for revert:
This CL break video_VideoDecodeAccelerator and video_VDASanity on all ChromeOS
boards.

BUG=715957

Original issue's description:
> gpu: Completely remove GpuProcessHostUIShim.
> 
> The only remaining purpose of GpuProcessHostUIShim was to send messages
> back and forth between GpuProcessHost and the ozone platform. Move that
> relevant code into GpuProcessHost, and remove the ui shim.
> 
> For ozone: Remove GpuPlatformSupportHost::OnChannelEstablished(). It is
> currently needed only for the drm implementation, and is essentially just
> a thread hop from the IO thread to the UI thread. So do that from inside
> the drm implementation, instead of having a public API and requiring the
> gpu host do the thread-hop.
> 
> BUG=709332, 711333
> 
> Review-Url: https://codereview.chromium.org/2820463002
> Cr-Commit-Position: refs/heads/master@{#466351}
> Committed:
https://chromium.googlesource.com/chromium/src/+/63c1e2603b28e1fb6a2ca120e793...

TBR=jbauman@chromium.org,dnicoara@chromium.org,rjkroege@chromium.org,jam@chro...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=709332, 711333
==========