gpu: Remove testonly header files from service_sources target.

gpu: Remove testonly header files from service_sources target.

These headers are intended to be consumed by tests only, not by
production code and thus should not be listed in service_sources target.

This makes the following errors disappear:

ERROR at //gpu/command_buffer/service/gpu_scheduler_mock.h:9:11: Include
not allowed.
          ^----------------------------------
It is not in any dependency of
//gpu/command_buffer/service:service_sources
The include file is in the target(s):
//testing/gmock:gmock
which should somehow be reachable.

ERROR at //gpu/command_buffer/service/mocks.h:22:11: Include not allowed.
          ^----------------------------------
It is not in any dependency of
//gpu/command_buffer/service:service_sources
The include file is in the target(s):
//testing/gmock:gmock
which should somehow be reachable.

Tested on Linux with the following command lines:

$ gn gen out-gn/Debug
$ gn check out-gn/Debug //gpu/command_buffer/service/*

BUG=367595, 376000
TEST=see above
R=sievers@chromium.org

Committed: https://crrev.com/d1d9e928cabf90e24d17fc2b12b67bfe4b9d7431
Cr-Commit-Position: refs/heads/master@{#327384}

[tfarina, 2015-04-28 19:15:56]

PTAL!

https://codereview.chromium.org/1114633003/diff/1/gpu/command_buffer/service/...
File gpu/command_buffer/service/BUILD.gn (left):

https://codereview.chromium.org/1114633003/diff/1/gpu/command_buffer/service/...
gpu/command_buffer/service/BUILD.gn:79: "gpu_scheduler_mock.h",
I will remove this in a follow up. I want to keep this change focused only on GN
and no other changes mixed in.

[no sievers, 2015-04-28 20:05:38]

lgtm

[tfarina, 2015-04-28 21:35:32]

The CQ bit was checked by tfarina@chromium.org

[commit-bot: I haz the power, 2015-04-28 21:36:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1114633003/1

[commit-bot: I haz the power, 2015-04-28 23:09:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-28 23:10:30]

Patchset 1 (id:??) landed as
https://crrev.com/d1d9e928cabf90e24d17fc2b12b67bfe4b9d7431
Cr-Commit-Position: refs/heads/master@{#327384}