[tflite] Add macro registration for type string to typeToTfLiteType.

PiperOrigin-RevId: 204210338

tensorflow/contrib/lite/BUILD

@@ -146,6 +146,7 @@ cc_library(
         ":memory_planner",
         ":schema_fbs_version",
         ":simple_memory_arena",
+        ":string",
         ":util",
         "//tensorflow/contrib/lite/kernels:eigen_support",
         "//tensorflow/contrib/lite/kernels:gemm_support",

tensorflow/contrib/lite/allocation.h

@@ -23,6 +23,7 @@ limitations under the License.
 #include "tensorflow/contrib/lite/context.h"
 #include "tensorflow/contrib/lite/error_reporter.h"
 #include "tensorflow/contrib/lite/simple_memory_arena.h"
+#include "tensorflow/contrib/lite/string.h"
 
 namespace tflite {
 

tensorflow/contrib/lite/interpreter.h

@@ -63,6 +63,10 @@ template <>
 constexpr TfLiteType typeToTfLiteType<std::complex<float>>() {
   return kTfLiteComplex64;
 }
+template <>
+constexpr TfLiteType typeToTfLiteType<string>() {
+  return kTfLiteString;
+}
 
 // Forward declare since NNAPIDelegate uses Interpreter.
 class NNAPIDelegate;