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

gpu/command_buffer/common/constants.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_CONSTANTS_H_
 #define GPU_COMMAND_BUFFER_COMMON_CONSTANTS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
+// From glextchromium.h.
+#ifndef GL_SYNC_TOKEN_SIZE_CHROMIUM
+#define GL_SYNC_TOKEN_SIZE_CHROMIUM 24
+#endif
+
 namespace gpu {
 
 typedef int32_t CommandBufferOffset;
 const CommandBufferOffset kInvalidCommandBufferOffset = -1;
 
 // This enum must stay in sync with NPDeviceContext3DError.
 namespace error {
   enum Error {
     kNoError,
     kInvalidSize,
@@ skipping 53 matching lines @@
   IN_PROCESS,
   MOJO,
 
   NUM_COMMAND_BUFFER_NAMESPACES
 };
 
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_CONSTANTS_H_