Automated sync from github.com/tensorflow/tensorflow (#2567)

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

tensorflow/lite/core/c/common.h

diff --git a/tensorflow/lite/core/c/common.h b/tensorflow/lite/core/c/common.h
index ea54be9..96f19f1 100644
--- a/tensorflow/lite/core/c/common.h
+++ b/tensorflow/lite/core/c/common.h
@@ -472,6 +472,8 @@
   kTfLiteCustomAllocationFlagsSkipAlignCheck = 1,
 } TfLiteCustomAllocationFlags;
 
+enum { kTfLiteNoBufferIdentifier = SIZE_MAX };
+
 /// A tensor in the interpreter system which is a wrapper around a buffer of
 /// data including a dimensionality (or NULL if not currently defined).
 #ifndef TF_LITE_STATIC_MEMORY