message: Extended ScratchSpace to expose its underlying scratch tensor object.
diff: @@ -313,6 +313,9 @@ class ScratchSpace {
  int64 size() const { return scratch_tensor_.NumElements(); }
  const string& debug_info() const { return debug_info_; }
  + Tensor& tensor() { return scratch_tensor_; }
  + const Tensor& tensor() const { return scratch_tensor_; }
  +
  // Returns true if this ScratchSpace is in host memory.
  bool on_host() const { return on_host_; }
  