Revert of Added SyncToken command buffer trait to help with IPC messages.

Revert of Added SyncToken command buffer trait to help with IPC messages. (patchset #1 id:1 of https://codereview.chromium.org/1394543003/ )

Reason for revert:
Broke gpu_unittests on Android. e.g. from the tombstones for this CL's run:

I   42.987s Main  signal 7 (SIGBUS) at 0x7569c97a (code=1), thread 15602 (st:test_process)
I   42.987s Main
I   42.987s Main  tombstone_06 created on 2015-10-08 01:00:00, about this long ago: 0:11:29 Device: 03d130ac006adc26
I   42.987s Main  Reading native crash info from stdin
I   42.987s Main  Reading Android symbols from /b/build/slave/android/build/src/third_party/android_platform/development/scripts/../../../..
I   42.987s Main  Reading Chrome symbols from /b/build/slave/android/build/src/third_party/android_platform/development/scripts/../../../..
I   42.987s Main  Using toolchain from :/b/build/slave/android/build/src/third_party/android_platform/development/scripts/../../../../third_party/android_tools/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-
I   42.987s Main  pid: 15669, tid: 15669, name: st:test_process  >>> org.chromium.native_test:test_process <<<
I   42.987s Main  signal 7 (SIGBUS), code 1 (BUS_ADRALN), fault addr 7569c97a
I   42.987s Main      r0 7569c972  r1 00000000  r2 00000000  r3 00000000
I   42.987s Main      r4 7569c972  r5 00000000  r6 0000007b  r7 00000000
I   42.987s Main      r8 00000052  r9 4004e678  sl 00000001  fp 400b2384
I   42.987s Main      ip 00000000  sp bef25480  lr 75441b59  pc 75441b5c
I   42.987s Main
I   42.987s Main  Stack Trace:
I   42.987s Main    RELADDR   FUNCTION                                                                                        FILE:LINE
I   42.987s Main    00329b5c  gpu::SyncToken::SyncToken(gpu::CommandBufferNamespace, unsigned long long, unsigned long long)  /data/app-lib/org.chromium.native_test-1/libgpu_unittests.so
I   42.987s Main    00077699  __static_initialization_and_destruction_0(int, int) [clone .constprop.176]                      /data/app-lib/org.chromium.native_test-1/libgpu_unittests.so

Original issue's description:
> Added SyncToken command buffer trait to help with IPC messages.
>
> R=piman@chromium.org
> BUG=514815
>
> Committed: https://crrev.com/6a219f8ccdd5148f28458b8184f31859babb9848
> Cr-Commit-Position: refs/heads/master@{#353170}

TBR=piman@chromium.org,dyen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=514815
Committed: https://crrev.com/77970f1c3cd71d535a248d6e15f14081312b300a
Cr-Commit-Position: refs/heads/master@{#353440}

[jbudorick, 2015-10-10 00:34:46]

Created Revert of Added SyncToken command buffer trait to help with IPC
messages.

[commit-bot: I haz the power, 2015-10-10 00:38:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1386323004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1386323004/1

[commit-bot: I haz the power, 2015-10-10 00:43:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-10 00:44:59]

Patchset 1 (id:??) landed as
https://crrev.com/77970f1c3cd71d535a248d6e15f14081312b300a
Cr-Commit-Position: refs/heads/master@{#353440}

[David Yen, 2015-10-10 00:47:50]

lgtm