Issue #1288 - Part 1a: Update brotli to 1.0.7

This also reorganizes the exports in the build system to use `brotli/`
as include directory.

modules/brotli/enc/literal_cost.h

@@ -0,0 +1,30 @@
+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Literal cost model to allow backward reference replacement to be efficient.
+*/
+
+#ifndef BROTLI_ENC_LITERAL_COST_H_
+#define BROTLI_ENC_LITERAL_COST_H_
+
+#include "../common/platform.h"
+#include <brotli/types.h>
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+/* Estimates how many bits the literals in the interval [pos, pos + len) in the
+   ring-buffer (data, mask) will take entropy coded and writes these estimates
+   to the cost[0..len) array. */
+BROTLI_INTERNAL void BrotliEstimateBitCostsForLiterals(
+    size_t pos, size_t len, size_t mask, const uint8_t* data, float* cost);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif
+
+#endif  /* BROTLI_ENC_LITERAL_COST_H_ */