Fix macro args in bin_decoder.c

src/core/ext/transport/chttp2/transport/bin_decoder.c

@@ -82,12 +82,11 @@ static __inline bool input_is_valid(uint8_t *input_ptr, size_t length) {
             (decode_table[input_ptr[1]] >> 4))
 
 #define COMPOSE_OUTPUT_BYTE_1(input_ptr)        \
-  (uint8_t)((decode_table[ctx->input_cur[1]] << 4) | \
-            (decode_table[ctx->input_cur[2]] >> 2))
+  (uint8_t)((decode_table[input_ptr[1]] << 4) | \
+            (decode_table[input_ptr[2]] >> 2))
 
 #define COMPOSE_OUTPUT_BYTE_2(input_ptr) \
-  (uint8_t)((decode_table[ctx->input_cur[2]] << 6) | \
-            decode_table[ctx->input_cur[3]])
+  (uint8_t)((decode_table[input_ptr[2]] << 6) | decode_table[input_ptr[3]])
 
 bool grpc_base64_decode_partial(struct grpc_base64_decode_context *ctx) {
   size_t input_tail;