message: adding InputTensor class for symmetry with OutputTensor
diff: @@ -257,6 +257,15 @@ class Node {
  TF_DISALLOW_COPY_AND_ASSIGN(Node);
  };
  +// Represents an input of a node, i.e., the `index`-th input to `node`.
  +struct InputTensor {
  + const Node* node;
  + int index;
  +
  + InputTensor(const Node* n, int i) : node(n), index(i) {}
  + InputTensor() : node(nullptr), index(0) {}
  +};
  +
  // Represents an output of a node, i.e., the `index`-th output of `node`. Note
  // that a single `OutputTensor` can correspond to multiple `Edge`s if the output
  // is consumed by multiple destination nodes.
  @@ -268,8 +277,6 @@ struct OutputTensor {
  OutputTensor() : node(nullptr), index(0) {}
  };
  -// TODO(skyewm): add InputTensor if/when necessary
  -
  class Edge {
  public:
  Node* src() const { return src_; }
  