[TF] Variant improvements.

1. Change Variant Decode to accept VariantTensorData (non-ref).

This should allow some optimization in the future.

In the meantime it means removing the variant.h include from tensor.h, since
variant_encode_decode.h now relies on tensor.h and variant.h now relies on that.

It also means we found a bunch of places where tensor.proto.h, variant.h, and
mutex.h were being imported through tensor.h (along with a bunch of other crap);
so now we directly import them in order to compile.

2. Move Variant registry to use TypeIndex instead of a TypeName string; this should
speed up registry lookups.

PiperOrigin-RevId: 212478896

1 files changed, 2 insertions, 2 deletions

diff --git a/tensorflow/core/kernels/data/iterator_ops.cc b/tensorflow/core/kernels/data/iterator_ops.cc
index fe6d705eab..30c6585ba2 100644
--- a/tensorflow/core/kernels/data/iterator_ops.cc
+++ b/tensorflow/core/kernels/data/iterator_ops.cc
@@ -403,12 +403,12 @@ class IteratorStateVariant {
   }
   string TypeName() const { return kIteratorVariantTypeName; }
   void Encode(VariantTensorData* data) const { *data = *data_; }
-  bool Decode(const VariantTensorData& data) {
+  bool Decode(VariantTensorData data) {
     if (data.type_name() != TypeName()) {
       return false;
     }
     std::unique_ptr<VariantTensorData> tensor_data(new VariantTensorData);
-    *tensor_data = data;
+    std::swap(*tensor_data, data);
     std::unique_ptr<VariantTensorDataReader> reader(
         new VariantTensorDataReader(tensor_data.get()));
     status_ = reader->status();