message: Remove parens and use CHECK macros in UniqueOpGPU
diff: @@ -86,7 +86,7 @@ Status ExtractFirstOccurrenceIndices(const GPUDevice& d, int64 input_size,
  const TIndex* sorted_input_unique_ids,
  TIndex* unique_input_inds,
  TIndex* segment_ends) {
  - if (input_size == 0) return Status::OK();
  + CHECK_GT(input_size, 0);
  GpuLaunchConfig config = GetGpuLaunchConfig(
  input_size, d, &ExtractFirstOccurrenceIndicesKernel<TIndex>,
  /*dynamic_shared_memory_size=*/0, /*block_size_limit=*/0);
  @@ -157,7 +157,7 @@ Status LookupAndScatterUniqueIds(const GPUDevice& d, int64 input_size,
  const TIndex* sorted_input_unique_ids,
  const TIndex* inv_sorted_unique_perm,
  TIndex* idx) {
  - if (input_size == 0) return Status::OK();
  + CHECK_GT(input_size, 0);
  GpuLaunchConfig config = GetGpuLaunchConfig(
  input_size, d, &LookupAndScatterUniqueIdsKernel<TIndex>,
  /*dynamic_shared_memory_size=*/0, /*block_size_limit=*/0);
  @@ -363,12 +363,12 @@ class UniqueOpGPU : public AsyncOpKernel {
  // Sort by input index so that output is in order of appearance.
  OP_REQUIRES_OK_ASYNC(
  context,
  - (GpuRadixSort(context, uniq_size,
  + GpuRadixSort(context, uniq_size,
  /*keys_in=*/unique_input_inds_ptr,
  /*keys_out=*/sorted_unique_input_inds_ptr,
  /*indices_in=*/static_cast<const TIndex*>(nullptr),
  /*indices_out=*/sorted_unique_perm_ptr,
  - /*num_bits=*/Log2Ceiling(input_size))),
  + /*num_bits=*/Log2Ceiling(input_size)),
  done);
  // Free temporary tensor that is no longer needed.
  