message: Fix Cardinality() of SkipDatasetOp when count < 0
diff: @@ -30,7 +30,7 @@ class SkipDatasetOp : public UnaryDatasetOpKernel {
  void MakeDataset(OpKernelContext* ctx, DatasetBase* input,
  DatasetBase** output) override {
  - // Create a new RepeatDatasetOp::Dataset, and return it as the output.
  + // Create a new SkipDatasetOp::Dataset, and return it as the output.
  int64 count;
  OP_REQUIRES_OK(ctx, ParseScalarArgument<int64>(ctx, "count", &count));
  @@ -72,7 +72,7 @@ class SkipDatasetOp : public UnaryDatasetOpKernel {
  if (n == kInfiniteCardinality || n == kUnknownCardinality) {
  return n;
  }
  - return std::max(0LL, n - count_);
  + return count_ < 0 ? 0 : std::max(0LL, n - count_);
  }
  protected:
  