Automated sync from github.com/tensorflow/tensorflow (#2308)

BUG=automated sync from upstream
NO_CHECK_TFLITE_FILES=automated sync from upstream

Author: TFLM-bot

tensorflow/lite/c/builtin_op_data.h

@@ -15,6 +15,9 @@ limitations under the License.
 #ifndef TENSORFLOW_LITE_C_BUILTIN_OP_DATA_H_
 #define TENSORFLOW_LITE_C_BUILTIN_OP_DATA_H_
 
+/// For documentation, see
+/// third_party/tensorflow/lite/core/c/builtin_op_data.h
+
 #include "tensorflow/lite/core/c/builtin_op_data.h"
 
 #endif  // TENSORFLOW_LITE_C_BUILTIN_OP_DATA_H_

tensorflow/lite/c/common.h

@@ -21,6 +21,9 @@ limitations under the License.
 /// interpreter and the operations are C.
 ///
 /// For documentation, see tensorflow/lite/core/c/common.h.
+///
+/// See also c_api_opaque.h which has more ABI-stable variants of some of these
+/// APIs.
 
 #ifndef TENSORFLOW_LITE_C_COMMON_H_
 #define TENSORFLOW_LITE_C_COMMON_H_