Added an extra sync token field for extra command buffer identification.

gpu/command_buffer/client/client_test_helper.h

Index: gpu/command_buffer/client/client_test_helper.h
diff --git a/gpu/command_buffer/client/client_test_helper.h b/gpu/command_buffer/client/client_test_helper.h
index ae464e96ae9a36e33f3f2446409c130dcc35ef41..8592fbcb630b42789d718be1ae9d2a74613f3a50 100644
--- a/gpu/command_buffer/client/client_test_helper.h
+++ b/gpu/command_buffer/client/client_test_helper.h
@@ -115,6 +115,7 @@ class MockClientGpuControl : public GpuControl {
   MOCK_METHOD0(IsGpuChannelLost, bool());
   MOCK_CONST_METHOD0(GetNamespaceID, CommandBufferNamespace());
   MOCK_CONST_METHOD0(GetCommandBufferID, uint64_t());
+  MOCK_CONST_METHOD0(GetExtraCommandBufferData, uint32_t());
   MOCK_METHOD0(GenerateFenceSyncRelease, uint64_t());
   MOCK_METHOD1(IsFenceSyncRelease, bool(uint64_t release));
   MOCK_METHOD1(IsFenceSyncFlushed, bool(uint64_t release));